4 reasons why it was the right move to have Daniel Bryan retain the WWE Championship
#3 Bryan just introduced a new belt
The entire purpose of building a new belt out of scratch was to have Daniel Bryan carry it around his shoulder and bragging how he protects the Nature by denying anyone else the opportunity to bring back the "non-eco friendly" WWE Championship.
This one itself is a convincing reason to not take the belt off Daniel Bryan, atleast until WrestleMania 35.
#2 The other challengers have different storylines, little credibility, or other factors
All five challengers for the WWE Championship have some quality that stopped WWE to hand it to them at the moment.
Randy Orton and AJ Styles will start a non-title rivalry heading onto WrestleMania 35. Samoa Joe is still in a rivalry with Mustafa Ali. Jeff Hardy has little to no credibility at the moment. Kofi Kingston is still a part of the New Day and the WWE officials always refrained themselves from making one member of a stable, comprising "equal" members, more important than the others. Although the last one may sound absurd, WWE mostly follows that rule in a stringent manner.