At my previous company, we used tools from all over the place. We switched between tools at will. Sometimes, some team would decide to use some tool while the rest of the company would use something else. The worst part was that there was no Single-Sign-On (SSO) either. Everyone would need to have an account on all of these said tools. It was chaos.

I realized that being integrated into one environment (even though would have the cost of a vendor-lock-in) was the best option to have because in that case, we wouldn't have to deal with operational hurdles like having integration from one tool to another. They would just come baked-in with the whole environment. That's how GSuite (formerly Google Apps for Work), Atlassian and other players succeeded - they gave a complete suite of services / software that integrated well with each other. You could jump back and forth between services without having to bother about integration with other tools. They'd all be there wherever you wanted them to be. Even cloud providers so that opportunity and built on it - Amazon Web Services (AWS), Google Cloud Platform (GCP), Kubernetes (in itself).

Another example is a company that used Jira, Confluence and Hipchat but for some dumb reason used Gerrit for their code review / hosting. Eventually, they realized that managing the integration with the Atlassian tools was far more expensive than getting bitbucket and migrating completely into the Atlassian environment.

It's always the integration that matters. Everything else is secondary.