Is there any practical benefit to this, or is it just for looks?
Yes, personally I finger f__k the clit at slide lock and during use. Cutting it flush causes less wandering finger. I don’t bevel the stop or counter sink the frame now, I just grind them close, put some tape on the frame and file it flush then hit it with a polishing stick. It takes alittle extra time during assembly but I don’t have to worry about popping a slide stop out during manipulations.
The second reason is clearancing laser grips as I understand. Other than that, itis pure looks.
I have the right side of the slide stop cut flush on most of my 1911’s. As a left hand shooter, my right thumb makes contact and puts pressure on the “nub”. I’ve only had one 1911 where my right thumb would drive it’s non-flush slide stop to the left during firing and cause a consistent malfunction. That was enough for me. Having the flush cut is reassurance for me that it is most likely to happen.
I have heard this is beneficial for lefties, It also looks great! I am in the process if acquire a 100 degree counter sink to do my frame. I think checkering the end to contrast is a great touch as well.