For reasons that you and I have expressed before ...
I don't question that you did but if I did express that view, I must have done it under the influence of Ambien. What I did express, as I recall, is that there are theoretical but practically immaterial speed gain going from 4-bit to 8-bit.
Many of the newer LCDs for example can work with the EN pulse between 100ns - 200ns. And they boot up almost instantaneously (can be initialized in a matter of ms). Code calibrated on those LCDs would not work on a regular HD44780.