My point of view is slightly different as a compressor is a critical part of my sound. I use it as a shaping device to slot the bass in the mix the way I want. Most of my gigs(on electric not upright) are on large stages playing pop/country/rock. A compressor set correctly allows my sound to be more controlled and fit in the mix better. The comp I use(Origin Cali76-CB), also adds color to my tone that lets the bass cut a little better and be heard clearly. I don't use a compressor as a crutch, but more as a tone shaper. Do you need one? Its completely dependent on the player, and their tonal goals. You may not need one, but you may also find it an indispensable tool. The best way to find out is to try one for yourself!