What are useful situations to use the 'Sprint Slide' skill in?

I'm not exactly sure what the 'Sprint Slide' skill is useful for (compared to simply crouching).

So, what are useful situations to use the 'Sprint Slide' skill in? Can it improve stealth approaches? Any actions with unique results that can be done through it?

It can sometimes be useful to quickly pass under an obstacle which otherwise requires crouching, like a low and narrow bridge when you run in a creek bed or a tree log laying over a path.

Just remember that after the slide, your character is in the crouched state, so in order to not lose the valuable milliseconds you just gained, immediately press sprint again to get back into the sprint state.

Personally, I use it for two things:

1. Getting to cover fast
2. Extending my sprint a little longer - I try to time it right to hit the sprint slide at the end of my sprint (when he cannot sprint anymore and has to catch his breath)

Other than that - Kotekzot is correct that you need it to unlock more skills.

Sprint slide is mainly useful for 2 purposes:

1. Looking cool.
2. Unlocking actually useful skills.