Not surprised - they have a mature product which is admittedly a bit ropey in quite a few places but it stands up for us and scales well enough. We've developed great plugins for Confluence which tie in nicely with Comala workflows and delivers a robust document management solution. Cannot see us moving anywhere else anytime soon.
And yes, I've run and admin'd a ton of these systems over what is now decades, so IMHO these are still great. REST api is a bit hit and miss, but if you wish to tool rond these apps, you can. Cloud is defintly where it's all going - who wants on prem anymore?