The 25K pedal is for active set ups; the usual volume pedal for guitar / bass is 250K or 500K, either of which will have less tonal suck at lower volumes. The 25K pot will reduce you're volume fine, it's just that EB make them in two resistances to match active or passive better. If you do use it after effects, the 25K will fit in just fine. But I do agree with the comment above about letting your effects play out while controling input into themthat is, pre effect.
I almost won't play guitar without a volume pedal (right after the guitar) but with bass I haven't wanted to use it. I've tried a few times and find I can control dynamics fine with touch, even for "swells."