Whats the reason for it to suck in your opinions?

I think it works pretty good. Pull-Requests are easy to follow, you can even suggest minor code changes directly in your comments or create Jira tickets for follow-up tasks. Commit history is nicely readable. CI works very robust and has lots of possibilities. Project level permissions and branch settings are easy to create. I have nothing to complain really

Bitbucket makes total sense for companies thanks to the Jira integration and wide range of integrations with the CI pipelines.

As a private person, why would you ever use an Atlassian product?