It kind of works - sometimes. Or I don't know how to use it or need some practice to use it :-)

I think without any visual indicator or marker it is very inconvenient to set point A and B with the same keyboard shortcut.

Please add a visual indicator and/or marker and perhaps provide three distinct keyboard shortcuts -
1. Setting Point A,
2. Setting Point B and
3. Reset and clear both points.

And consider to provide some visual feedback as soon as those keys are pressed.

For the time being I'll be using looptube.io instead.