[Capricorn2481]

Not really. That's like saying a wrestler is only in the match for a few minutes so why do they need all of that training.

Speedrunners are often playing the game or parts of the game hundreds of times. And they're usually performing techniques that take lots of precision and therefore lots of practice.

So they stream it all, documenting their attempts and trying new strategies in front of a live audience. They produce so much comment that there are YouTube channels that make documentaries about different speedrunners.