Sami Zayn made history on SmackDown tonight, defeating Solo Sikoa in a thrilling main event to capture the United States Championship for the very first time in his storied career.The crowd in Lyon, previously having been called the greatest one in WWE history, was loud throughout the night and firmly behind Sami throughout the main event.Fans erupted in genuine elation when Zayn pinned Sikoa following two Helluva Kicks to win the title, and based on the internet's reactions, it has taken some members of the WWE Universe by surprise. View this post on Instagram Instagram PostWhile the decision may have been a bit surprising, considering it is rare for WWE to have major title changes without months of building a feud, here are four key reasons why Sami Zayn became the new United States Champion by defeating Solo Sikoa tonight in Lyon.#4. To deliver an awesome moment for an awesome crowdSmackDown as a show has been rather underwhelming in recent months, but the shows this week and the last one have been much better, with how invested the European crowds are being a major factor. According to John Cena, the consensus backstage among the WWE roster is that last year's Backlash in Lyon featured the greatest WWE crowd they had ever performed in front of.It made sense, therefore, for WWE to not just return to Lyon ahead of Clash in Paris, but give the fans a worthy show and a worthy moment to cap it all off. Well, what could be better than Sami Zayn, the ultimate babyface and crowd favorite, winning a title he has never won, following a brilliant main event in front of one of, if not the hottest, WWE crowd of the year?#3. To allow Solo Sikoa to move on to concluding his feud with Jacob FatuAfter months of torture at the hands of Solo Sikoa and his MFTs, Jacob Fatu allied with Jimmy Uso and then Sami Zayn to take them down. The ultimate point of this storyline will, of course, be Sikoa getting his comeuppance at the hands of Jacob Fatu, but if WWE had no plans to put the United States Title back on Fatu, then Sikoa obviously would have had to lose the championship before going down to Fatu, which Solo did tonight with his loss to Sami Zayn.There was really no reason to extend Solo's title reign or delay Sami Zayn's moment anyway. If WWE wants to move right on to concluding Solo vs Jacob before The Samoan Werewolf moves on to bigger and better things, then the time was now, and WWE made the call to strike. Hopefully, the company has concrete plans for Fatu beyond the Solo Sikoa feud, because he is a major and unique asset who needs to be presented in the right situations and surroundings.As for saving the match for a bigger occasion, as outlined, time and timing were crucial in this case; WrestlePalooza was too far away, and putting Sami vs. Solo on Clash in Paris was obviously never the plan. Sikoa has always been a better TV wrestler anyway, considering his in-ring psychology and how TV matches are structured. The SmackDown main event allowed Sami Zayn to give Solo one of the very best matches of the latter's career, and the match probably wouldn't have been as good on a PLE.#2. Sami Zayn can help steer SmackDown back on track as the United States ChampionThere are innumerable reasons why SmackDown, as a show and a brand, has been a major disappointment over the past few months. But Sami Zayn's arrival on the blue brand brought a ray of hope to begin a resurgence, and thankfully, WWE was smart with expediting his United States Championship win. Zayn, with his iconic status, can now begin to elevate talent on SmackDown as they step up to him in a bid to win the United States Championship.Zayn is a complete package and the ultimate utility player, who can craft compelling short-term and long-term narratives, revisit older stories with Cody Rhodes, Drew McIntyre, Jimmy Uso, etc., build matches and characters with a microphone in his hand in one night, and deliver in the ring better than almost anyone on the roster.Heels like Carmelo Hayes, Aleister Black, and even babyfaces such as Andrade, Rey Fenix, Damian Priest, and Johnny Gargano can continue to step up to him in open challenges and short-term programs, allowing SmackDown's deep yet, for whatever reason, underutilized mid-card to step up. It would build up fellow wrestlers, but also build up the quality of SmackDown shows and provide a direction and structure to the blue brand.#1. To make a case for a Royal Rumble win and World Championship reignWhen Sami Zayn wins the big one, it is going to be a moment in time. The Montreal native is one of the absolute greatest of this generation, and among the best wrestlers to have never won a World Championship. For years, he was underutilized in WWE. While many consider that he became a made man in The Bloodline Saga, the truth is that Zayn perhaps did even more for that faction and storyline than he got in return.Zayn has very compelling dynamics with the likes of Roman Reigns, Jey Uso, Seth Rollins, Cody Rhodes, Drew McIntyre, and, of course, Kevin Owens. There are perhaps too many ways WWE can route Zayn's path to his first World Championship, but with next year's Royal Rumble in Saudi Arabia, there is a massive opportunity floating about.If WWE indeed pulls the trigger on a Royal Rumble win and hopefully a World Championship win at WrestleMania, Sami Zayn needs to be elevated to that level, not in terms of star power or ability, but as a wrestler who is presented strongly. A run with the United States Championship will now allow Sami Zayn to pick up major wins against serious talent, and also serve as a trial run for when he does eventually capture the WWE Championship or the World Heavyweight Championship, where he'd then have even more compelling stories to tell.