By now it is widely used in my family as backup for our smartphone photos and important documents on PCs. In addition we use it for our calendars, contacts, notes and passwords.

I'm also investigating whether it's useful to track recipes for the food we normally eat to help manage our usual "what should we eat today" and "what groceries should we buy this week" questions.

I use it to manage my documents, backup my photos from my phone to my server and access all my files from any other device. Basically Nextcloud is my replacement for OneDrive.

Additionally, I have used it in the past to collaborate on various group projects which require documents. For example, I had to make a presentation with some other people and I could create a PowerPoint in Nextcloud, send a share link to others and then we could edit the PowerPoint in realtime with Nextcloud + Collabora, which is pretty cool. It's the only FOSS alternative (at least as far as I'm aware of) that can compete with Microsoft 365 / Google Workspaces.

I use it to sync all my photoshop projects and documents from my different machines to my server and to have access to those files from my phone , it's the first thing I install when I do a fresh install of my os since everything I use is there

I like it as basically a self-hosted Dropbox/GDrive for syncing and sharing. I would love for them to focus more on that (performance especially, as others have noted) instead of all the other crap they keep trying to jam into it.

I used it mostly for calendar and adressbok synchronization between devices bit the performance was so bad O had to replace it.

Could you expand a bit more on the LDAP part? I'm thinking of rolling something like that myself but not sure if it's worth it