Many bulk license discounts usually apply, but the narrative of "free and good enough" isn't really useful as it's not the case at all on either account. And you cannot mix and match lower tiers; the highest tier someone needs in your org defines what you pay. Yes, office licenses are bundled with Teams licenses, but you're paying quite a bit for it as a business regardless of how useful it is for most of your day to day work.

While Teams might seem nice in that it has connectors for power bi or bots or other loose integrations with other services, this ecosystem is not very mature or populated and at least from my experience, it's mostly in the hands of the System Admins who manage Teams/Azure for a company; you need to run resources on Azure or self-host most of the integrations (excepting the prebuilt apps like Polly (poll tool for polls in Teams)), you need to manage resources on Sharepoint/OneDrive as the data lives there, etc.

It starts to really add up after awhile. I don't think the main selling point of Teams is as a chat app, but instead as a monitoring app. Microsoft Viva will give you little reports on your work usage which is presented as a healthy work-life-balance helper, but ultimately it's just an employee monitoring tool. [1],[2] It was sold and pushed as the single business analytics tool from Microsoft with complete visibility into your employee time/work; from what I've seen on the Admin Center, it's quite deep in what it analyzes, despite a lot of the functionality it uses for monitoring being quite buggy (e.g., Status tracking is a non-trivial amount of reporting, but the actual Teams app status gets stuck all the time)

Teams is not a chat application, it is a monitoring application that can also do chat/video and monitor said chat/video. It is questionable in most orgs I've seen whether this feature is really useful/necessary once it's actually deployed, as the takeaway that managers have from the same reports is usually pretty vastly different and there are a wide range of interpretations applied. (this last part doesn't just apply to teams but all employee monitoring apps, but that is another discussion entirely)

0 - https://www.microsoft.com/en-ww/microsoft-teams/compare-micr...

1 - https://learn.microsoft.com/en-us/microsoftteams/teams-analy...

2 - https://learn.microsoft.com/en-us/microsoft-365/admin/activi...