Rice paladin question on 2 skills

Every guide I look at seems to have volatile reversal in it. I don’t understand this skill at all and use it incorrectly more often than not.

I was looking at sigils of hope.

Should I replace volatile with sigils of hope? Why do high level ppl love volatile reversal?

Do I have to button mash sigils of hope for it to work correctly? I do enjoy barely ever having to hit volatile due to the long cooldown.