Apparently there are several companies that are using MS Teams, according to MS. Although MS boasts about 13m users or something, it's interesting to note that 13m is only about 10% of users who have O365 subscriptions (and get Teams for free). Which means MS can't seem to convince 90% of their subscribers who already have Teams for free to actually use the product.
not easy. O365 has individual users and schools that don't need Teams but even free is a hard sell bc you're coupling chat with Office and a company might not want to stick with office later on or get everyone office.