I don't consider myself old (early 30s). I sometimes say "no problem" or "no worries" in response to a thank you ... but specifically, it's when I'm doing something to fix something that someone else did, or cover for them, that sort of thing. In other words, I'm trying to communicate that it wasn't a problem for me to help them out.
As opposed to responding to thankfulness for something "nice" or "kind," which would get something along the lines of the traditional "you're welcome."
Using the restaurant example, I wouldn't expect "no problem" to a "thank you" unless they were like, cleaning up something I spilled or something. If I said thank you for them bringing my food to the table and they said "no worries," that'd be a bit weird.
So yeah, I view it as being some what more communicative. It's not just "you're welcome," it's "no problem, don't worry about it/feel bad, it wasn't a big deal." Which doesn't make sense in all contexts, but I think it does in some.