They finally get some closure with their father in a way that doesn’t feel like the end of the show.
Because if we had just brought him back and it had been like, ‘And then they go and hunt a demon together,’ it wouldn’t have been satisfying.
It’s not like, ‘And now roll credits, we’ll never see you again!’
It feels like it allows these guys to put some, not all, of their 14 years of baggage down and move on to the future maybe with some new knowledge, maybe a little bit more unencumbered.