Having done some UX work in this area, I can say that people greatly overestimate the effects of latency on text entry when they're just looking at the numbers. End-to-end lag is more obvious in situations like dragging objects, but even then people manage to work around it.
Typing isn't performed on a tight feedback loop in the brain. We don't wait for the letter to appear on screen before starting the process to press the next key.
Typical human reaction types are on the order of 250ms for a simple visual stimulus. Recognizing letters will take even longer. A difference of a few 10s of milliseconds isn't generally going to be noticeable for typing unless you're really going to great lengths to A/B test.
Consider that people can SSH into remote machines all of the time with 100s of milliseconds of latency. The experience may not be optimal, but our typing doesn't fall apart over SSH.