Good for you, and, I quit too. But the reason I joined is that I miss out on a lot of in-person interactions, because friends of mine use fb to invite folks to events. What you're describing as a "superficial relationship" was actually "membership of a few small groups." Interacting with those people was a positive in my life, and I miss them. It's not just okay, but actually healthy, to have relationships that aren't lifelong and deep.
I bemoan the loss of "church community" despite never having been a churchgoer. It's nice to show up, blend in, make time with a few familiar faces, and leave. Non-intense social interactions are good. People who only have intense social interactions tend to have bad social anxiety, because their brain isn't accustomed to anything between zero and 100. The good part about fb is that it can be used to facilitate that. I'd happily have a profile on the Facebook Events platform, if it existed as a separate product. But since it necessarily comes with all the other baggage, it's healthier for me to miss out.