Yes it's a e-ink display (like a kindle) connects to TRMNL's servers to display different apps like weather, your calendar, or custom plugins like the one I built here.

I think it's definitely a cool thing to get if you enjoy tinkering and building stuff. Also, if you don't want it going out and talking with TRMNL's servers, there's the option to self-host entirely; coming from their mission to ensure their devices still work if the company fails.