It's not very hard to understand...
Something based on reflexes = not everyone is capable of doing it.
Something based on memory = potentially 99% of the people can pull it.

If everyone can do it, it's not difficult.

What I've found hard in videogames until now? Stuff like:

Red bull challenge in GT5 (people screamed for nerfs because only like 1% were capable of getting gold there xD, and it wasn't a matter of repetition, some people weren't going to succeed even if they were to live 7 times xD).

Certain bosses from the soul games in very low levels. One single mistake and you are one shot.

Now...a scripted battle? It's like saying that memorizing a paragraph is hard. Please get real.

If you want a real challenge or something that really proves your skill, go to any populated PVP moba and make it to the top 100. You are going to make it through real difficulty in order to get there. No artificial difficulty involved.

And no, it's not "different kinds of difficulty". One thing is difficult, the other one is not.