Okay, but integrating 3rd party platforms was done a long time as well, Dropbox integration was IMO the central feature that allowed ownCloud that time to become even a bid relevant, I guess was possible right from the start (?), and social plugin integration for Twitter, Facebook via social sharing apps starting with NC12 as far as I remember, then RocketChat, of course Collabora online (external server connector) etc.
I think both is good, offering own, completely self-hosted solutions and as well offering to integrate the big conventional solutions, at best to allow a seamless transition for users, same as with Dropbox => Nextcloud for the core data storage and sharing functionality. That transition was btw more than once topic in the NC conference talks the last two days .
Not sure about that, I was using
Spreed.ME that time, even learned how to create systemd units and wrote a HowTo about that to get the server running from boot on (my goodness, I didn’t know what a systemd unit is 3.5 years ago ), and I remember that a lot of users complained and raised issues and finally didn’t use it because it was too complicated and stood with Skype instead. Nextcloud Talk integrated WebRTC server changed that radically.
In case of OnlyOffice, even as standalone server it was already a big enhancement over Collabora online when it’s about setup effort and system requirements but a feature is likely MUCH more used when the whole install/setup is not more then hitting the “Install” button in the Nextcloud app store. I cannot really evaluate the effort for creating this built-in compared to the previous connector app for the standalone server, but when you take
development time per end user as the relevant metric, I guess a complete integration wins in very most cases.
And remember the shared hostings, where users have often not the possibility to install additional servers, so a full built-in is the only possibility.
Finally the NC usage survey might give some answers when comparing the share of users that used the OnlyOffice connector app (before the built-in was released) with the share of OnlyOffice built-in users and connector app users now .