Can’t say I agree. You can mimic all of these features you place as advantages by connecting Drive, Docs and Slack via Zapier. The flexibility of Drive folders and integration with Google Suite and the superiority of the entire Google Apps ecosystem, on the other hand, provides additional advantage.
Unless you are a software development company, you don’t need JIRA for project management or product development. And if you are using Slack, you actually don’t need anything else. There are a couple of great todo bots for Slack that get the job done right in your channels.