They have a large inventory so if you want to handle a specific gun there's a good chance they'll have it so you can put your hands on one to decide if you want it ... then buy it online.
(EDIT: was instaposted by HoneyBadger)
They may have figured out that is what we use them for, but in the past I've taken people down there looking for a specific gun and we got to handle several and they were polite about it (although the clerk swept us with the muzzle ... which annoys me but happens at most shops).
But I haven't been in there in a couple years so I can't speak to what they're like today.