They are not wireless but the sub is. They then connect to the sub with ~20' cables provided in the package(You get everything you need & then some!).
It's nice that way because you can set the sub up behind your couch/chairs or whatever & run the rears to where ever you want to place them behind you.
No, you do not have to use them or the sub if you don't want but that's kind of a waste of buying the complete system.
Overall the set sounds really good, looks nice, & I haven't had any problems with any of the features I've used yet & it was easy to set up.
Well worth the small price for what you get. If you want more you're going to spend a lot more to get it.