Barely noticeable while gaming. Rhythm games for sure, but otherwise my biggest complaint is that all 2.4ghz headphones are "gaming" headphones. Not many low latency high end options.
Unfortunately, my game is not a rhythm game. I basically can't tell which of my shots hit the target. If I shoot 3 times in 300ms, I don't hear the first shot until I click the second time, so if I miss the first shot, it sounds like I missed the second shot, it's very jarring
But I know what you mean, those headsets with a separate dongle work good enough. Shame really, that Bluetooth hasn't caught up by now, except some barely supported low-latency codecs
Not only standard itself, but also low quality implementations both in hardware and software. And while major OSes' BT stacks continue to gradually improve over time they won't help you if you Bluetooth hardware or device you are trying to connect to (again both hardware and software) are trash. It's a curse of every open standard, no matter how good or bad it is by itself - there always will be shitty implementations. And if there are a lot of them (like in case of BT) then majority of them will be shitty.