First off, do it for yourself. If the audience can hear it as well, great. They definitely could hear it in the small clubs I played.
In bigger clubs, first question is do they run a stereo PA? Many do not, but my suggestion of sending one stereo channel to FOH and one to the stage works really well in some cases.
A lot of guys will tell you that the stereo image will be missed by too many in the audience. If you use radical EFX like ping ponging, everyone will hear that to some degree, in my experience. Be sure to get at least ten feet between your cabs, and consider only going stereo above 250Hz or so. I got the idea for the three channel system from Pat Metheny, who supposedly got it from Jaco. I was using the rig for guitar and guitar synth as well as bass, and the stereo aspect is very important for many synth patches. I know some guys who loop bass who insist on stereo rigs too.
On more thing is: what happens when you run in mono with all that stuff? Spread cabs create issues then, and it bears consideration as to whether you'll get less throw and definition at that point.