"BTW, why "Save as video" can be only found in the "Save as" icon, but not in the "Save Special" menu? "

I remember reporting that years n years ago when I was rendering to videos.
There was another also, Song Form Dialog that was only accessible from the button I requested many times over the years because visually impaired users needed it, it was only implemented this year because someone in beta kept asking for that same reason.

Same with other buttons like UserTracks, Loops, MIDI Super Tracks there is no menu access to them from keyboard, that's why I think this menu is very much needed. Even a custom menu where users can add what they like without me having to make hacks.