I think I even said so on here before the move happened when someone mentioned Phoenix as an option.
I’d guess they just thought there was literally no downside. Sign him for 10 games, if he sucks, you let him go, if he’s good, you’ve got a team option on a cheap bench player for next season.
Ticketing/merchandise sales might have played a role, but I doubt that was the primary motivating factor.
I think it’d be cool if he could find a role in Phoenix, but I’m not sure it’s a great fit. Hopefully he can play better the rest of the season and either have the suns pick up his option or show enough that another team gives him a contract.