@vampiress for comparison, my current MP3 (well, FLAC) player - a Shanling M0 Pro - is based on an Ingenic X1000, a MIPS system-on-chip with about 32 megs of RAM and a comparable amount of horsepower to that Pentium 200. It is super useful to me in that use case. You could probably get a lot of utility from it.
I think @nev has a different use case but similar motivation to extract maximum utility from performance-light systems?