#3 So that Rey Mysterio can focus on the feud with Seth Rollins
So, Seth Rollins has embraced the darkness in him and gone over to the dark side, allying with Akam and Rezar AKA The AoP. It is very clear that Rey Mysterio and Kevin Owens are at odds with this trio.
To even the numbers, I'm guessing that Samoa Joe will also be inserted into the mix. This is a program with enough heat that does not need a Championship, and I'm guessing that this may even be highlighted more than the US Championship picture.
As the central storyline on RAW in the absence of Brock Lesnar, Rey Mysterio had to relinquish the Championship and get into his extremely heated feud. Who knows... if Andrade is to split from Zelina Vega, he may even turn face and join the good fight with Rey Mysterio!
But I don't think that's the best course of action for Andrade, and instead, the following point is...