If you’re a DC and you see Moss in the game you’ve probably prepared all week to call the game a certain way. Utah knows this and likely game planned to exploit the defense they expected to see when Moss was on the field. So, even if he isn’t 100 percent, you keep him out there so that they have to keep run personel on the field.
It could also be an in game adjustment. For example, if we notice that whenever Moss is in the game they play an extra LB and we think we can exploit that LB by making him cover a slot WR, then we would want to keep Moss in even if he split out wide.
So, to answer you question, zero utility. We don’t intend to use him as a reciever out there. It’s more a strategy to force personel matchups we find favorable.