There are people that have no physical issues, but just aren't very good at games that end up grinding for dozens of hours to make it through. Some people bash their head against bosses they find hard for hundreds of attempts before they get it. Some people try a boss a few times, decide it's impossible, and then summon someone to beat it for them. Souls games have many routes towards success that don't boil down to "reduce boss damage to 50%".