I don't think it's meaningless. It's an incremental step in tightening access to firearms.
You are aware there are crimes committed with guns besides mass murders, right? I find it very likely that expanding backround checks would prevent at least some bad actors from legally obtaining firearms. Now, you guys have flooded the country with 300 million firearms so there's an enormous black market that will have to be dealt with as well of course. But my point about legal access stands.