[fluffything]

Anything that requires real-time interaction between a client and a server and other clients, e.g., gaming, stadia/geforce now, videoconferencing, ...

< 100ms is usually the "minimum", > 150ms is often "unusable", and for a smooth experience you might need < 30ms depending on the application (e.g. depending on the game you might need < 90ms or <60ms or <30ms).

[Dylan16807]

Videoconferencing does not need imperceptible latency.

The other two things on your list are both gaming.

[michaelt]

Depends how much you care about people talking over one another. If your call is a presentation/lecture/class with few switches between speakers, latency's no problem.

But if your calls normally have lively discussion where someone different jumps in any time there's a pause, the higher the latency the more likely people will say "meeting in person is much better"

Likewise, with things like remote desktop, 100ms of latency isn't a dealbreaker but it'll certainly leave some of your users saying "things that run locally just feel snappier"

[fluffything]

For mobile phone networks, >20ms latency in audio is "unacceptable" from the point-of-view of standards conformance and a client "accepting" the hardware of some vendor.

Up to 100ms is kind of ok-ish barely-sluggish, but over 100ms latency, it becomes extremely annoying to maintain a conversation.

Video conferencing often makes this worse, because it is what people use for meetings, etc. and that involves more than 2 people maintaining a conversation, so latency becomes even more important there.

Otherwise 3-4 people start talking over each other, and none of them notices until they receive what the others are saying. Which is extremely annoying.