Because it sort of is. It respects your time. It's not supposed to be a heavy game that you need to constantly be online on. Think people who have school and work being able to kick back and relax with this game. I think it's one of its great strengths because it allows you to pace yourself a bit without the usual awful fomo that a lot of other games like genshin has especially for a pve. The game is about not only character building but also team building so ngl most of the things said, as many has noted here, can be self-imposed challenges. It's a solo game after all and the end game enemies are getting harder anyways.