When I was picking up my antenna and coax cable for my cb install I saw a pa speaker for 10$. Since I put it in my kids and I have had a blast with it. It doesn't really serve a purpose but it was cheap and fun.
I say go for it.. my wife don't get it nor does she get the cb. She actually said I'm such an old man. Kinda stung a little since I'm only 34. I like them both and think they were a good mod to add so that's all that matters.