A house bass makes sense in a jazz context because we're often playing DB and having several of those hanging around is a bit of a nuisance, particularly in some of the cramped pub venues we have to play in.
Recently I've been bringing an EUB I got cheaply on Ebay; it doesn't sound as good as the acoustic but will do for the jam, and in any case there are several players who turn up with bass guitars. When they want to play then the EUB fits nicely into a coat rack, out of the way. It is also easier to carry, which means I can bring guitar kit for the large part of the evening when a bass guitarist is up.
My personal opinion, which others are sure to disagree with, is that anyone who plays guitar or bass guitar should bring their own to a jam and not complain if others aren't willing to hand theirs over to strangers in a pub.