Middle click is held when you scroll, only pastes if normal quick click. Never have had an issue with accidental pastes, unlike the trackpad which I do palm on occasion and cause various accidental events. You can zoom with ctrl-middle click, I used to have that rebound to just ctrl-trackpoint but in the situations where I am using the trackpoint I tend to prefer zooming with the keyboard so that binding got lost along the way. No idea if there is a binding for scrolling through the history, I never interact with my history that way, you can always do a custom binding.

>Trackpoint seems much less ergonomic and less useful than a trackpad to me.

You still have a trackpad, it is not either or. For more mouse heavy tasks I prefer the trackpad or trackball if it is handy. For things which require lots of back and forth between keyboard and mouse, I prefer the trackpoint. Everywhere else is a mix, scrolling a long website I tend to use the trackpoint but for general browsing tend towards the trackpad, editing this post I will use the trackpoint but will almost certainly use the trackpad to click "reply" since my fingers will be going back to general browsing mode. I just use which ever is most suited to the task.