>>50483631This. Allowing people to take their original investment further into the established scenario is better than forcing everyone to start anew.
It's interesting Nintendo also explicitly mentioned the Expansion Pass as the major cause of its increased DLC performance last year in their financial report. They don't do numbers, but if it even sold half of what the base game had sold at that time, it would have comfortably outsold all released third versions at that time, with those extra sales being people who wouldn't have bought the third version, because it meant having to start from scratch again.