Oiless pumps are good for painting since you get cleaner air. 30 gallon really isn’t big enough for a half inch impact for serious use. For the hobbyist it should be fine. What I mean is, you may get one ten lugs off and then have to wait a few minutes to build some air back up before doing ten more. A good half inch impact will eat 4-5 cfm @ 90 psi. A quick look at Lowes’ website shows 1.5 hp oiless at 4 cfm. They would do the job for your needs.
I use a much bigger compressor, but I need it to run my IR261 when I need to get violent with noncooperative fasteners.
Oiless compressors have a higher pitched BBBBRRRRRRRR where oil types are more of a thumping sort of sound.