I think the more compelling reason for 80x24 is that it works out reasonably well to do the arithmetic for it by bit-shifting. 64x16 displays used to be common because that works out even better. I think the IBM PC went to 80x25 because that's as many as you can fit in 2048 bytes without going over, and they were willing to spend a lot more chips on video than earlier microcomputers were.
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I think the more compelling reason for 80x24 is that it works out reasonably well to do the arithmetic for it by bit-shifting. 64x16 displays used to be common because that works out even better. I think the IBM PC went to 80x25 because that's as many as you can fit in 2048 bytes without going over, and they were willing to spend a lot more chips on video than earlier microcomputers were.