It's built using Catalyst, their technology for running iOS apps on MacOS, which was only launched with Catalina, so there's a good reason for this.
I recently got a new Macbook and was dreading having to use Catalina, having heard horror stories online, but actually my experience has been fine. A few security popups to click through when you first run a new app, but some of the screen shots I saw online of hundreds of them must have been fake, it's really not a problem. Having to right click and open unidentified apps can be annoying, but I'd rather do that and keep Gatekeeper on personally, rather than disabling Gatekeeper entirely.
It actually feels really solid so far (granted its a clean install on a new laptop) and I am really impressed with the Sidecar feature in particular. Of course, if you depend on 32-bit apps or drivers, or certain apps which are meant to be buggy (e.g. Mail referenced in another comment), you may want to hold off for a while!
The reason you didn't see the bevy of popups was because you did a clean install.
With an upgrade install all of your existing apps have to go through the same security steps as a new app, and they tend to do it all at once, especially if you have a lot of apps that launch at startup.
That said my experience was not as extreme as some of the screenshots, and I think it would be even less for the average user. And of course this is only upon first upgrade, so while frustrating, you quickly get over it.
I upgraded last weekend and I think the only new security prompt I had was from Bartender 3, which needed some new "screen recording" permission to see what menuextras you have installed. Had to go into the Security preferences and turn that on manually rather than just having an "OK" button, but it wasn't hard.
Oh, and Terminal had a popup for permission to access ~/Desktop
Damn! I really enjoyed Swift Playgrounds on the iPad, but found the lack of real keyboard irritating. I was about to download this until I saw your comment.
My email's too important to risk upgrading to Catalina still.
I've heard there were data store migration problems and haven't had any myself, but is this even an issue if you're using IMAP? It's all stored on the server anyways. (I can't imagine using POP in this age of multiple devices.)
Yep, definitely an issue with IMAP mailboxes. It's not a storm-in-a-teacup-because-it's-Apple situation, it's an Apple-really-done-fucked-up situation.
