68 series CPU vs 80 series CPU
The Intel 8080 family of processors used a parallel bus that, among other things, had separate strobes for read and write cycles.

The Motorola 6800 family of processors used a parallel bus that had a single R/W line to indicate whether a cycle was read or write, and a separate E (enable) strobe to indicate that a cycle was occurring.

It's trivial to convert between the two schemes (either way) with a few gates, but it was a big deal at the time that LCD controllers could connect to either style of bus without "glue" logic.

On a modern microcontroller, you're pretty much bit-banging the interface with GPIO pins anyway, so it's an arbitrary choice as to which style of bus you prefer to implement.