According to the source, Microsoft wants to make the taskbar appear to float above the desktop by separating it from the desktop and rounding off the corners.
In an effort to make the user experience even shittier? Or maybe one of the suits saw their kid with a custom linux desktop and was like: we need to get these kids off that linux crap, and clearly the floating task bar is the clincher! *does a giant rip of cocain *
Whenever Explorer.exe crashes, it takes down the desktop including the taskbar. They are probably trying to separate the taskbar from the desktop.
It's a new style and people expect to see a unique style with every Windows version change. Of course, if you really want to you can make Windows 11 look like Windows 98 with a few button presses afaik.
3 a) It potentially looks like they might start auto-hiding the taskbar by default which could be interesting. If they are and they allow applications to maximize to the full borders of your monitor, that could potentially be awesome.
3 b) auto-hiding the taskbar frees up real estate and if you put on a tin foil hat you can say that Microsoft is going to use that newfound real estate to show ads to users and will justify it because they only take up less space than you were missing before, it's no big deal, right? (This is highly unlikely and Windows as an OS hasn't really shown people ads yet. The most it's done is shipped with minor bloatware apps.)
Windows as an OS has absolutely been showing ads for a long time. Ads for their own stuff for the most part, but those are still ads. They pop stuff up all over the place advocating for paid OneDrive plans or Office 365 or whatever.
Those aren't ads embedded in the OS. Those are ads because an app is installed. It's also fairly easy to uninstall them. Also, all over the place is a bit silly. It's like once via the notification system when you first install the OS.