Most AV receivers have their binding posts in a tight field that makes it a real chore to wire 12 ga into the sides.
Banana plugs let you do a neat wireing job. (Neatness is very important here - any stray strands of copper can cause a short.)
Nobody I have heard of can hear the difference between 2 speakers where one is wired with bananas and the other with bare wire. So there is no audible difference.
The Dual banana plugs from Radio Shack (xxx-308) are great for behind your speakers. The solid spacer bar prevents shorts should a kid/dog yank the speaker wires while the power is on. (Note: The spacing of binding posts are not standard so buy 1 set and bring them home to see if they fit your speakers/receiver). For behind the receiver, the Radio Shack single bananas (xxx-306) dont stick out as far.
CON:
The banana plugs ARE friction fit so they could tug out. But they do make "Locking Banana Plugs" that need a twist before they get released.
On the other hand, a quick-disconnect could keep your receiver from being pulled out of your rack should something strong snag a speaker wire and pull.
Unless test eqpt has BNC connections for it's leads, it propably has bannana plugs.
If it's what I use to verify a good v. bad signal, I bet it's fine for speaker wire connection. Also I feel that the tight fit of a bannana combined with formentioned convience show a clear path to persure.