Latency is cumulative, so avoidable latency is never acceptable. Maybe the hardware will change. Maybe somebody will run your software in an emulator. That 5ms could be enough to push the total latency into the "annoying" level.

And even with no additional latency, 5ms is perceptible in some cases anyway. Microsoft Research has a video demonstration:

https://www.youtube.com/watch?v=vOvQCPLkPt4

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inigyou an hour ago | parent [-]

Do you really think the people who programmed your microwave should have taken into consideration that someone might write a microwave emulator in the future? Dealing with that is not their job, it is the job of the emulator creators.

	▲	crote an hour ago \| parent [-]
		Who says the emulator is "unauthorized"? For example, smartphone app developers routinely run their apps in emulators first to make the development process more convenient, only running it on a physical device for confirmation when the work is basically done. Many embedded developers would kill for something similar, and we're already seeing the start of it with platforms like Wokwi. Being able to do integration tests without the physical device itself is an absolute game changer.