It really all depends on the kind of style and type of music that you play. If you're driving lines in a punk/rock/metal band for example, you probably don't need any compression, as you would be maintaining the same loud dynamic throughout. However, if you were to be playing something which demands a more delicate touch, perhaps involving harmonics or if you were slapping, compression would be very helpful to even everything out and retain a sensible level of volume for all the notes that you are playing, be they slapped, popped or lightly plucked.
In my band I play out gentle harmonics in some songs together with sustaining notes underneath them and sometimes slap, so it's a helpful little tool to bring some control to my bass signal. Especially as I also use a multitude of effects, and compression before an octave pedal helps it to behave nicely, so I use it as an always on pedal; I just set it and forget about it. Yeah I can get away without using compression, but I don't like to as without it I have to rethink some of my basslines, to compensate for the dynamics of different playign styles.