You're correct that full value parallax won't apply unless your eye is at the far extent of the viewing field of the scope.
However in a hunting scope where shots may be made from odd angles, parallax error can add 1/8-1/4" or so to your groups.
Example: 32mm objective, with a fixed 50yd rimfire parallax adjustment.
at 10yds, you have a max parallax error of 12.8mm (very close to .5")
At 25yds OR 75yds, you have a max parallax error of 8mm (.315")
At 100yds, your max parallax error is 16mm or .646"
Cut those values in half for a realistic "shot around a tree while sitting" shot, and you can evaluate whether or not that works for you.
FWIW, I shoot with a 4x Tasco fixed 50yd parallax scope (an old Tasco with good glass), and a Clearidge 3-9x32mmAO on my .22s. Both are fine scopes.
