I love the idea of an acoustic bass in sessions, though I expect there will be those who disagree. I never take my double bass anywhere as it's a royal pain in the arse to lug around. Electric basses are frowned upon at such sessions in my experience, and I have been told not to bring one to one session which would benefit from bass, and I don't have an acoustic bass guitar yet.
As with any instrument, know when to sit one out, and know to play the role.