If I were shooting with full frame only, I wouldn't need a 50mm lens in my bag.
In fact, for many years while shooting film, I didn't own one... Or when I did (a lot of cameras came with one), didn't bother taking it out much.
50mm angle of view on a FF/film camera just doesn't do a lot for me. It's a personal preference, I like to use slightly wider and slightly longer lenses instead... 35mm and 40mm, 85 and 90mm, depending upon system... and really didn't need the lens in between these.
Now with crop cameras it's different. I find the 50mm very useful as a short tele and just wouldn't want to be without it. I've compromised on a 28mm as my "normal" lens, which is only slightly wide on a crop camrea, but has served pretty well. If a 24/2 USM existed, I'd probably use that instead. I don't care much for 30mm, 35mm or 40mm on a crop camera.