I agree with all of your points, I just wanted to highlight I just learned about a few months ago, that maybe others don't know about as well :)
> - more practical because of the ubiquity of mouse wheels for easy up/down navigation compared to the various less common ways of navigating horizontally
You can actually do horizontal scroll by holding shift and scrolling the wheel. Learning this was a revelation.
"You can actually do horizontal scroll by holding shift and scrolling the wheel."
Yep, that is helpful. But note that this is no universal standard. But most mainstream applications and browsers have it indeed implemented. Useful for big pictures etc.
I thought this was implemented on the OS level or something like that, as I've never not been able to use it for horizontal scrolling. I'm mostly on Linux but worked everywhere on Windows as well as far as I can remember. Maybe on macOS it's different.
It's likely possible to force that mapping via some configuration tools. On Mac and Windows, such tools are usually rather visible, but on Linux it's probably just config files for some components of X or the input layer.
> - more practical because of the ubiquity of mouse wheels for easy up/down navigation compared to the various less common ways of navigating horizontally
You can actually do horizontal scroll by holding shift and scrolling the wheel. Learning this was a revelation.