The Mac App Store is a trap - The sandboxed APIs are severely limited, and no large company is going to let Apple get even more in-between them and their customers.
First, they can use the sandbox without going through the Mac App Store. Sandboxing is a good idea regardless of distribution method. That would improve security for everybody, without needing to 'let Apple get in between them and their customers'.
Second, Zoom already runs sandboxed for the other two ways you can run their client on Apple operating systems: the (iOS) App Store and the web. The Mac sandbox is the least strict of the three. So whatever they do, it doesn't seem to be hindered by 'severe limitations'.
I have yet to hear any feature that a legitimate videoconferencing application would need that would be disallowed by the macOS sandbox. Lots of other video chat apps are on the Mac App Store, like Facebook Messenger. Is the issue simply that Zoom is being sketchy and wants to continue to be sketchy, and sandboxing would not allow them to? That's not because the MAS is 'a trap'. That's its main feature.
The issue is not technical. It is political. Apple is arbitrary and capricious, and no one sensible wants every update to their software to be held hostage to Apple's whims. Large companies like Facebook can cut special deals.
Then I'm simply not going to install it. The only apps I have ever installed from the App Store are OS upgrades and I think Apple's office software, since neither is available outside of the store.
And these apps deserve to have “breaking opening from Finder” and even more restrictions considering they have shown themselves to be completely untrustworthy, insecure, invasive and hostile.
I had this problem with Office. Powerpoint had fidgety dialogs every time I wanted to open a pptx file from a different directory. I wasted two weeks, deleted it, and reinstalled from the direct download.
