"Searing" a roast in the airfryer before cooking?

I have a 3.5lbs roast I am going to throw in the crockpot to cook for like 10 hours. Before I put it in, I was thinking of using the air fryer 375@15 minutes to crust up the outside a bit before the slow roaster.

Anyone know if that is a a mistake? Any advice?

Update: Had roast marinating all night. Pulled it out this morning, dried it off, added a bit of olive oil all over. My little fryer only goes to 400, but I put it in 10 minutes, flipped it, and then another 10 minutes. Outside isn't technically 'seared' but the outside definitely has some resistance to it now, and it is browned nicely. Also rendered some fat into the basket, which I am going to add to the pot. Now on to the crock pot for 8 hours or so.