Reasons they sometimes switch from long-lived Meet calls:
- Free up 200-300 MB of RAM when in call.
- Features specific to coworking (e.g. shared music DJing) or eng pairing (e.g. multi-way screen share).
- Presence when out of video calls. For example, you'd see if anyone on your team is in the Meet without having to ping each other. Leads to more unplanned hang outs.
I do understand that macOS APIs and libraries are easy to use, development experience is (at least in my opinion) better than with Electron + framework of your choice, and you can achieve better integration with the OS, but I don't think that saving 200-300 MB is really important to the end users.
So some people are very glad to save RAM, CPU, etc. Others don't care but love shared music DJing etc...