It's just wrong. He asked what we miss. Noone said what we miss has to be rational.
I do see your point about it always being available.
It just feels out of place on the dock. It's more a folder (to me at least) than an app. And even if you think of it as an app, why is it sitting over with the minimized windows?
And it's nice to have the trash can in the same place all the time. The only way to do that on the dock is to pin it to the left bottom, the bottom right, or the right bottom - all of which are extremely awkward.
And, generally, if you're dragging something to the trash, you already have the desktop showing (to get to your folders), so the desktop trash is already visible.
Or maybe it's just me.