I'm a new player (4 hours new). This DLC only adds more grind so you have enough resources (they're hard to come by already, especially at the beginning!) to buy trinkets (they're expensive!) and 'befriend' creatures by playing a music instrument. Basically adds another in game 'wiki' that you have to fill by befriending critters and I suspect that's how you get a new achievement, after you vefriend them all. The fuss of the entire thing, as well as the trinkets are not worth it.
You'll progress naturally in the base game without this DLC. Plus, the critters that follow me only annoy and distract me. What's the point of this dlc? To be milked for money by the developer, with the base game already costing a fortune while it's not worth it?
I like the base game. This "DLC", however? I agree with the others, this should have been free content. Don't waste your money. Shame on the developer for being so greedy.