As an adherent to the 'stand there motionless and play, hopefully looking a bit moody'™ school of bass playing, I can't see much benefit for me. Plus it's another thing to carry and set up.
I am also an analog snob (for which read: self-imposed limitation), and most wireless systems are now digital, so that's another no.
But if it works for you, go for it, you won't hear me criticising (and I won't even be [i]thinking[/i] bad things about you).