Just finished the main game. Amazing 10/10. Now started Valhalla and erm...

Excuse my ignorance, but what is this? I don't see the point of it. Lost all my upgrades and armour and now just going in circles, doing the same thing over and over, with what feels like no real point? Is it something you have to stick with and it finally pays off? Or is this for people who like repetition with minimal gain?