First off, they're both good guns and will fit into this niche.
Ballistics is right in the same ballpark either way.
Reliability with the BW is excellent despite it being a rimfire, esp. if you carry CCI 22Mag ammo, as these have very reliable primers in my experience, the highest of any rimfires.
A small auto can of course jam. Despite the BW being a rimfire, I would rate a BW as more reliable than any small slidegun.
The P32 will have more firepower, faster reloads and faster shot-to-shot speed.
The BW will have a faster "first strike speed" coming out of a pocket holster with practice, and will be much cheaper to practice with using 22LR ammo.
Safety is a wash either way (and good for both).
The BW should be more resistant to pocket lint gumming or the sort of crud that can get onto an ankle-carry piece.
Upshot: if this is a backup, the "first strike speed" and reliability may be enough to offset the firepower/reload issues. At least in my opinion.