Minidisc used lossy compression, but did so before MP3.
Still being a physical format on a spinning disc, with a lossey codec devised early on, before much experience was gained, which was not well-rated... that killed it for me.
Sony at the time (as usual) was hoping to replace the open CD format with their closed format. It wasn't just about portability. They wanted to sell pre-recorded discs and kill the CD.
I'm amazed it has taken them this long to stop making them... I hope they lost money on it.
It made about as much sense as ministick memory.