to me, it's still worth it.
but at that point you need to try to get all your shots in a 1moa or smaller circle. so basically shoot for tight groups.
put yourself under a timer, and practice setting up positions and getting steady. the better you get, the "groups" will get smaller.
of course longer ranges would be BETTER, but you can still get valuable practice at 100yds. just need to make your target smaller.