For me personally, I find the way a ‘normal’ keyboard has the characters printed more aesthetically pleasing, but that is of course very subjective.
I think you are right that iso 9995 only targets staggered keyboards, I wonder if there is a difference in optimal character placement for readability speed between staggered, ortholinear or any other layout. Theoretically that could be formulated mathematically and tested in practice, but I doubt the benefit would be significant.
Thank you for the insight