Yes exactly, the interview itself is a bit less than half of the work surprisingly and then you do need a real break after all of that very intense concentration anyways. 1 interview = roughly half a day gone, that's what I've experienced.

And then it's indeed never valued inside the company, worse than that, it might be counted against you since you will achieve less in your team where all the evaluation will take place...

I really don't understand why companies don't value engineers capable of conducting interviews because it's really not an easy task, you need much better than average interpersonal skills and much better than average tech knowledge as well.