As a single-classed Factotum, yes, Able Learner does nothing. As a multiclassed Factotum (say, going into Chameleon) it does do something. When you're in another class, you keep the rank maximum of other classes' class skills, but spending skill points on skills that aren't class skills for your current class still costs double (as normal for cross-class skills). Able Learner keeps the cost at 1 per rank, like class skills.
If you don't come up with or can't decide on a viable alternative, just take a different feat initially, then retrain it at level 5 before you enter Chameleon. You could even use your level 6 feat to pick up whatever it was you originally took, I suppose.
I don't remember the exact house rules we're using here, but the ones in use for High Arcana include the effects of Able Learner as a base rule for everyone, so the feat would literally do nothing there.
