Musicians learn to lead the beat to account for the activation delay of their instrument - drummers start the downstroke before they want the drum to sound; guitarists fret the note before they strike a string… I don’t think keyboard latency would make rhythm games unplayable provided it’s consistent and the feedback is tangible enough for you to feel the delay in the interaction.
I'm a semi-professional keyboard player, and in the past I played with some setups that had a fair bit of latency - and you definitely learn to just play things ahead of when you expect to hear them, especially on a big stage (where there's significant audio lag just from the speed of sound). And some keyboard patches have a very long attack, so you might need to play an extra half beat early to hit the right beat along with the rest of the band.
If you watch an orchestra conductor, you may notice the arm movements don't match up with the sounds of the orchestra - the conductor literally leads the orchestra, directing parts before you hear them in the audience.
She's been learning Irish tin whistle for a few years, and is a big fan of the Dropkick Murphys and other celtic punk bands, along with 90s alternative bands lik Foo Fighters, Red Hot Chili Peppers, and Weezer. I've been learning guitar / bass / ukulele / mandolin, and it would be great fun if she can play drums and sing while I play something else....
I recall a guitarist friend who figured out their playing was going to hell trying to play to a track when their partner used the microwave. They were using an early (and probably cheap) wireless/cordless system and must have had interference.
On higher-end pianos (mostly grands), there is "double escapement" action, which allows much faster note repetition than without. I suspect the latency would be lower on such pianos.
> Musicians learn to lead the beat to account for the activation delay of their instrument
Yes, this is absolutely a thing! I play upright bass, and placement of bass tones with respect to drums can get very nuanced. Slightly ahead or on top of the beat? Slightly behind? Changing partway through the tune?
It's interesting to note also how small discrepancies in latency can interfere: a couple tens of milliseconds of additional latency from the usual — perhaps by standing 10-15 feet farther away than accustomed, or from using peripherals that introduce delay — can change the pocket of a performance.
It matters more in fighting games, where reaction time is crucial because you don't know in advance what your opponent is doing. Fighting game players are usually picky about their controller electronics for that reason, the net code of online games also gets a lot of attention.
In a rhythm game, you usually have 100s of ms to prepare you moves, even when the execution is much faster. It is a form of pipelining.
Some of them will batch multiple key presses over a slower connection interval, maybe 60ms, then the radio to USB converter blasts them over together.
So you can still type fast, but you absolutely cannot play rhythm games.
Lots of people might not be good enough to care about missing 1-2 frames.
One could also pre-load the wasd keys.