I think it's for environments where 2.4 is just trash and you'd rather not run any of it all, and your iot crap is the only reason you're force to still stand up a 2.4 AP in the first place.
This lets you go 5-only, and that's big for some settings.
I noticed yesterday how much traffic was on my 2.4GHz IoT network last night because my phone connected to it. TBH I have no problem with everything being on 2.4, I just wish it was common to have two 2.4 radios so you could have a true IoT-only network.
This lets you go 5-only, and that's big for some settings.