Yup, considering how unbelievably huge all the deck-builder games are I'm always a little surprised that more RPGs haven't done a good job integrating that sort of thing. 4e tried, 5e has had spell cards for a while (but there's just so many of them). I think they work especially with with DH's intentional design of limited "load out" + Vault as a mechanic of play. It's not just an "accessibility" thing, it helps track everything in a clean fashion as you level up and want to shuffle abilities around.
Not required, but nice to be included in a very reasonably priced core set (instead of how much Wizard was charging for each spell card box).
Edit: in fact, shades of Gloomhaven's design there.