The project is great and I made simple setup in docker to play around with it. There is official docker image you can use https://hub.docker.com/_/nextcloud.

The problem I see with similar services is they all trying to pack everything. You can also install external components into your system.

What it means in practice is huge area for security vulnerabilities, challenge to host/upgrade it at home on weekends and very complex user interface (easy to mess up with privacy settings).

I really scared to host such systems because of all related issues. Maybe it isn't big deal at all.

Probably, most of home use cases can be resolved by simple XMPP server (video calls, group chat, image/links sharing) plus some shared folder across the network to store some files/photos.