I no longer buy this argument these days. You don't need a "heavy" argument to avoid Teams, you need decision makers who can listen to teams other than the bean-counters.

Sure, it has integrations with the broader Microsoft suite and productivity ecosystems making it easier to approve if the org is a M/O365 org. However, this is not a universal state (Google Workspace, Zoho Workplace, etc), and if the decision maker actually cares about communication efficiency then Teams would never be part of the discussion. There's such a wide field for messaging and calling applications, just going with "easiest bundle that ticks boxes" is rather poor thinking (not that I'm expecting much from C-Suites these days).

I currently have to use Teams today across macOS, Linux, and Windows... personally, I would welcome switching to Google Chat (used at last gig) over this mess.