FB is a double-edged sword IMO. If you use it sensibly (and, importantly, avoid getting used by it) it can be very useful. I've spent a fair portion of my life overseas and have managed to make contact with many people from my past which otherwise would have been nigh impossible. Not life-changing I agree, but nice all the same.
I also advertise on it and have had good response.
Paradoxically perhaps, I use ad-blockers and an excellent extension called FBP (Fluff-busting Purity) which filters out about 99% of the 'noise' that makes FB so annoying. I also use Firefox's Facebook container so hopefully not too much data leaking out to the hungry data miners.