Well, the car has a cassette player. In it we have an adaptor to play ipods etc. through the unit.
I don't think that was where you were going though.
Too much wow and flutter for portable use when using cassettes for my tastes. I want music when I run...the mp3 player made that much more viable. I still remember fooling with various sports models, disc drive models, etc. "in the day". Yellow Sony units, Outback sony units, disc drive Sony units....etc.
Then went on to a dismal foray into minidisc for running. They skipped until the last generation. Same with portable CDs.
Dat tapes actually were not bad for running, just bulky. And expensive. But a certain cool weird factor went with those. Still have my portable DAT man!! (bet no one else here has one of those!!).