Hey there! So to me, the tokens are initially just ways to extend your run until your ending run, and to allow runs that have that Outer Wilds feel of being short or long depending on how things go.
I did want some ending variability. I wanted to encourage people to explore and look even on their last run, but to have the ability to skip certain planets (or all planets, if they were okay with a worse ending) if they wanted as they moved further in the game—sort of like being able to speed through a planet because you know it so well!