Their terms may have changed after they were acquired, I dunno. But Atlassian has something like two dozen different legal documents covering their software. How do you know what they do/don't do until you've had your legal department vet it?

As a random example: Trello can list any customer in their promotional materials (you have to dig through the legal docs to find the opt-out email). As the CEO of your own company, how would you like to see your company listed in a Trello ad when you're trying to do business with a Trello competitor, or gain a customer who competes with Trello?

Point being: employees use 3rd parties all the time in ways they shouldn't, often leaking a lot more data than meetings. It's why DLP is so popular.