I think people were "blown away" by three things. First, the lack of surface noise; second, the extended play time and not having to flip the record to the second side to hear a whole album; and third, doing away with the customary cleaning ritual needed before listening to music.
Those seemed to be the primary advantages for CD at that time. The simple utility of the media and ease of use were what convinced me to change from vinyl to CD. I still have a Thorens TD 165 turntable in a box somewhere with a Stanton 990 cartridge on it. Haven't seen it or used it for at least 35 years and don't care.