The standard way to install an application on the Mac is to simply drag it into the Applications folder. That’s what is expected by users. For the vast majority of applications this should be enough. Whenever I see a Windows-style “installer” the first thing I think is... what kind of shenanigans are going on?
This standard way doesn't work in corp environments (which WebEx and Zoom are targeting primarily), where machines are remotely provisioned. For decent macOS remote installs and updates you need the PKG format scripts.
What is so hard about remotely provisioning app bundles in a standard place? I ask because I have been tangentially involved in both image and script based provisioning and interacting with PKGs would seem to complicate, not simplify, both processes.
And the wacky PKG files used by Zoom (until recently) and WebEx are likely to be incompatible with those provisioning methods, because they don't unpack their contents and finish installing normally.
Still plenty of evil things you can do without admin privileges, like running a server in the background that launches Zoom (as they tried previously).
