Remember Microcassettes? They were a dictation medium (but so was the original compact cassette) Invented in 1969 by Olympus as the standard cassette started gaining traction as a popular music medium.
For a spell in the early '80s, Sony actually tried to make them as close to a serious audio medium as they could (as they did with the standard cassette.) Including stereo sound and Metal tape formulation microcassettes.
|The Microcassette Walkman even included a very rare microcassette version of the FM Tuner cassettes made for standard cassette personal stereos.|
In modern digital, It's like the sound of a 32 kbps MP3 to a 320 kbps MP3.
And secondly, people kept LOSING the handful of prerecorded albums on these tapes that were made for the Japanese market.
The Microcassette never went further into general use beyond dictation and in telephone answering machines. They have since been replaced by digital recorders.
Competing with the Microcassette (yes, it did have competing formats), was the Minicassette (developed in 1967 by Phillips) and the even tinier Picocassette (1985 by Dictaphone.)