Hmm, I get the idea, I remember I liked playing similar browser games where you crafted stuff over multiple hours and waited for things to be done.
I feel if it's something that's not in the browser and rather running in the background it needs some sort of audio or notification cue that it's done. I often forgot there was stuff running for me. Or maybe I'm just an Idle MMO casual, that could be it too. Still think there's a demand here, idle game renaissance soon.