SmartMedia cards were cool when they first came out. I remember the original Yamaha Motif that dropped a floppy drive in return for having a SM card. However, the bad thing is that due to the design of the card, the max size if 128MB, so this would be a great thing for MIDI, but for actual mixing and manipulation of uncompressed audio files, it wasn't that usable.
However, other formats have long since overtaken it. SD cards are the de facto standard these days, where one can buy cards up to 32 gigs.