I am curious, what is the unique selling point of Unity which makes people stick to it? Is it a global menu[1]? Dock? Support of legacy indicators?

[1]: GNOME3 has command pallete (ctrl+p) known from Sublime Text - https://github.com/p-e-w/plotinus

edit: Also https://github.com/lestcape/Gnome-Global-AppMenu

For me, it is possibly the menu/dock aspect, but for whatever reason it grew on me. I personally don't like the (Windows here) "click start -> hover applications -> drill down" method.

In the grand scheme of things, it is really just a taskbar in a vertical orientation, but I dunno, I just liked it after a while.

I understand the motivation of getting rid of it (the dislike of it from a lot of the user base, the development needs being able to be applied elsewhere, etc.) so I'm not going crazy over it or anything. Will miss it though.

It hasn't been necessary to drill down the applications in the start menu since windows 7. Just start, type search, enter. Then pin your frequent apps to the task bar.

Not necessary, but I'd argue it was still the predominant method for 7 and even 8 (from what I've seen people use, anyway). I do find myself personally with 10 using search a lot more (haven't had to observe others, so no idea about others usage), but sometimes I've had to shift over to the Win10 equivalent of the start menu -> applications method if I can't remember the name of the application outright (this was a bigger problem for me prior to Curse becoming part of Twitch, admittedly. They had two different clients and one of them was a bit more vague in naming).

I was more alluding to the gnome method which last I used it has a similar menu with the tiered folder structure. Maybe they have added search as well, but my memory of GNOME is too fuzzy so I had to go with the fresher (for me) Windows equivalent (granted, with Windows 10 the applications folder essentially hangs out to the left of the Windows 8 start screen-esque area so calling it Applications folder would be a misnomer on my part).

Unity is elegant and simple, yet offers all the functionality I need, has a minimal UI and keyboard shortcuts for everything.

Gnome3 is a collection of UI blunders and they (over)spend their funding on political bullshit I don't support.

reference?

It just works™. Plain simple window manager with good defaults.

Since 1995 I have tried every major window manager, nowadays I just use the default installations in any OS I use.

When you have an application maximized, its title bar becomes one with the status bar ( the one with time, network, weather and other indicators)

I think people initially didn't like it because it was canonical's attempt at "convergence" so that ubuntu could be used on PC/phone/tablet back when their plan was to run on those things. A lot of people hate the idea of a desktop OS that looks like a tablet OS. Anyway, I agree, over time I got used to it and don't really mind it now, certainly better than the old gnome 2 menu based desktop.

global menu, left side dock paradigm (integrated with top bar), the HUD.

Personally, I don't use unity, but I find these features attractive.

The HUD is on the latest Ubuntu MATE now and left side dock is one of the settings called Mutiny (inspired by Unity).

I believe that the Ubuntu Gnome Shell will have an extension to give it a Unity-like look, see the series of blog posts here: https://didrocks.fr/

No global menu though.