Not necessarily visually minimal, but conceptually minimal. It’s just the circuitry with a dipped coating over it, but I get what you are saying.
Good to know it isn’t a totally unexplored topic. The next time I’m at the store I’ll have to get some epoxy and a cheap flash drive to try it out. I know flash drives sometimes can get warm, but from my experience not as warm as most electronics. I guess one drawback could be that it would totally ruin any recycle ability, but how recyclable are circuit boards to begin with?