That's actually what I tend to do, but would be nice (for laziness) to have two different settings. Or for cases where games don't allow adjustment after starting.
Funny you bring up Kena, because that is actually probably a prime example for me too. Loved the rest of the game, but the boss fights were a bit too difficult imo!
Right? When I was a kid I would specifically enjoy the "challenge" of trying to beat something over and over. Nowadays though... I just like playing a game for the experience. I still like feeling "progression", so things go from difficult to easy as my character advances. But having to repeat something multiple times? Eh... just not my jam anymore.