#1 Why does Brock Lesnar need the briefcase?

Last year, the biggest active wrestler in WWE won the Money in the Bank briefcase to became the Monster in the Bank. He wasted his opportunity on Brock Lesnar a number of months later and has since fallen down the ranks in WWE.
This year, the playing field was leveled as Sami Zayn took Strowman’s spot in the match, but was attacked prior to it, which left him unable to compete.
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After the revelation, many fans wondered whether Strowman or Lars would take his spot, but it wasn’t until the end of the match that we found out who would take his place.
Brock Lesnar's music played and The Beast hit the ring. He tossed Ali from the top, scaled the ladder and retrieved the briefcase to win the match. It took him merely 30 seconds to do so after the other seven men battled for almost twenty minutes to take the briefcase home.
This raises only one question: is this win just to justify his match against Seth Rollins at the Super Show-Down? If that is so, it makes little sense as WWE could have easily gotten Paul Heyman to work up Rollins enough to accept a challenge from The Beast rather than have him cash in his briefcase at the event.
Brock Lesnar is one man who doesn’t need a briefcase to get opportunities in WWE, and him holding the briefcase makes the other seven competitors who took severe bumps during the match look like nothing.
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