Lots of good points have already been made. On the practical side, my experience of playing electric bass in a big band is you may be given a very tight spot to play in where inevitably you can't hear yourself that well (albeit that anyone over 6 ft away might be able to hear you a lot better). An ability to tip your amp up is good, or lift it off the floor on a milk crate. Some small combos (Hartke?) are designed to do that . However, floors (and walls) are also really good sound reinforcers. Staging can be good or bad at reinforcing sound (depending on what you are trying to achieve in the room). I have played a little Phil Jones combo which would be good with upright as well, as well as a 1/10 Markbass combo (louder). the key with both is they are quick to set up and don't take a lot of space.