Vertical layout is awesome for 8 bitters. We tended to use it a lot on the C-64, too.

The c64 had a very awkward native memory layout for bitmaps (8 bytes vertical corresponding to a 8x8 or 4x8 pixel block, then jumps back up, next 8 bytes again vertical but to the right of the first 8x8 pixel block!). Super annoying and the worst of all worlds for coordinate to memory address calculations.

So for demo effects we often used a purely vertical layout by abusing customizable character sets, which are allowed to have 256 fully custom 8x8 pixel characters: arranging the characters in, for example, an 16x16 character grid = a 128 x 128 pixel grid, such that the memory for the character set will effectively result in a vertically oriented mini bitmap.

This also has nice advantages for example for fast pixel filling: if you unrolled an EOR $address; STA $address; EOR $address+1, STA $address+1, etc. etc. loop, you had a pretty fast, almost constant time filler for a bitmap where you only painted top and bottom lines of the area you wanted to have filled - one line to switch on filling, bottom line to switch off again.