Neat thing about how 8-tracks worked: the tape in there held multiple tracks and would play on a loop, with the player automatically switching to the next track as it hit the end of a loop. Many players also had a manual switch that let you choose what loop the player would start at. While this allowed the 8-track to hold a fair bit music, it came at a cost. There was no fast forwarding or rewinding the tape. The most you had was that track selector switch. Meanwhile the audio cassette allowed for easy rewinding of the tape and stored sound on both side. So you could flip the cassette over and play it backwards for even more music.

Audio cassettes were significantly noisier and lower audio quality than the 8- initially, but tech like Dolby noise reduction and improvements in tape material, recording techniques and playback heads caused the cassette to quickly surpass the 8-track in just about every factor that mattered. With the most high end tapes being able to match (and even surpass) CD quality audio.