You'd be in the minority. Correct me if I'm wrong, but I'd bet you're at a small company where a low-level employee's opinion was taken into account when making the decision of which product to use for 10-50 people.

In medium to large sized companies, Atlassian will usually win out when you have a CTO that manages 100+ developers. Enterprises really like to stick with the "safe bet", where there are expensive licenses and dedicated account managers from the service provider.

Jira in particular is extremely popular with the modern addiction to Agile. Once you're on Jira, you just start to fall onto connecting all the related products like Confluence for wiki and Bitbucket Server (formerly Stash) for git. I'm not saying it's the best thing to just ignore all other offerings, but in my experience CTOs do exactly that and just go straight to Atlassian for everything.

Basically, if your company is using Exchange... expect to be forced onto Atlassian. Welcome to the enterprise.