Well he was already there having played Acapulco and he badly need matches...
He had more lows than highs last 15 months.
Plus Challenger is in same Venue like Masters some days after....
I think it is far from a bad move, Indian Wells is a very tricky place with desert wind, changing temperature, and high bounce.....Plus if it did not change that awfull 96 format where seeds have a bye and play opponents that have already a win under their belt causing usually lots of surprises among seeds that lack rythm.
Getting used to this conditons with a couple of double matches and some training sessions with his bro can help him....
7.07 Play-Up Regulation (ATP Challenger Tour Tournaments)
1) Players positioned 1-10 in the Emirates ATP Rankings twenty-one (21) days prior to the first Monday of the ATP Challenger Tour tournament are prohibited from entering, accepting a wild card and/or competing in an ATP Challenger Tour tournament.
In Singles and Top50 players do need a wildcard to enter Challengers. So yeah, no Singles for Zverev
Entering doubles in order to get used to the surface because he knows he has a bye in the first rd and he will plays someone in the second round, who is already used to the surface = smart. I’m shocked and I have to give credit where it’s due. Good thinking there Zverez