He's more of a "known" commodity at this point. And it would be cheaper for a team on the luxury tax. Take the Warriors for example at 48/51. They need some frontcourt depth, can use someone that can run the floor/rebound/screen.

Here's the relevant passage:

The Bucks appear to be interested in adding second-round picks this year because, due to a CBA quirk, those picks will only count for $898K against both the luxury tax and hard cap if they sign for the minimum. Undrafted rookie free agents, meanwhile, would count for $898K against the cap but about $1.62MM against the luxury tax.