which were quite expensive, including those who could afford frivolous luxury items like a Mac.
Indeed they were back then, and I will accept your argument that videocassettes were expensive when they were first introduced/gaining popularity (I still have one in the original shrinkwrap with the cost on the cover- $7.95 for a single Maxell HGX-Gold T-120 tape). My father purchased the first consumer Hi-fi VCR, which was a JVC HR-D725U back in late 1983/early 1984 for just over $2 500. We still have the unit today, although it requires new belts/caps after many hundreds of hours of use.
Moreover, it would have taken the user experience away from the Mac, and not allowed the interaction with the demo,
I still think a video demonstration would have been more appealing. A lot of people learn better through the help of visual aids. Either way, a videocassette would have lasted far longer than an audiocassette in terms of deterioration- those 84 guides must be completely brittle by now, and tape decks tend to eat more than conventional VCRs.
