Trading cards already exist, and they’re adorable.
As for achievements, that’s always a somewhat involved process – not just the pipeline of adding them, but having the game recognise them to begin with. And beyond that, what even makes a good achievement for a game like Stonehearth?
With that said, there’s a significant boost in sales for almost every game that adds achievements (it might be skewed by the fact that most games add them as part of a larger content update, though.) Given how many people list Steam achievements as a “pro” in their reviews on Steam as well, I’d say it would be a good tactical move if the team have time/the ability to make it happen.