But it’s still a smaller hex size and also probably half as deep, generally that design is crap and you should only use it if head profile is of paramount importance.
I use those round head hex on truck hardware on shortboards when I’m going to be standing on top of the screw head and a hex socket cap won’t make for a great foot surface.
In general, if you don’t have to use them, don’t use them. At all. Especially not if it’s for appearance reasons. It’s a huge mistake.