The hair growing back would cause all sorts of annoyance.
I have never waxed, but the way I understand it is you don't get this as it is "new" hair that grows back, which, even if you didn't wax, would grow anyway.
At the end of the day, it's upto to you what you do, I've often toyed with the idea of waxing, but never gone through with it, I just end up trimming/shaving.
Edit: I use a Phillips Bodygroom TT2030 which does a good job.



I must have sensitive skin. In all honesty I'm in two minds about having my back done again - I hate the look and feel of a hairy back but that rash is even worse (imagine what it must be like on your groin!). They did say that as your skin gets used to being waxed the rash isn't as bad.