They are but they give you power. How much power is still being worked out but some skills do get benefits when you're low on health. Seems like a very dangerous game of health management as low health usually puts you in execution ability range.

I’m curious which Set y’all thinking of

Only one I can think of is
Steadfast Hero
and I’m fairly certain that toggling off a skill will not qualify as a “cleanse”

But with ZoS....who knows...lol