The old coke bottle comes to mind. Everyone that has ever grasped something knows how to hold it.

https://www.interaction-design.org/literature/topics/intuitive-design

Imo it’s hosting stuff for yourself or your family. In cloud or closet. If you have an advanced nas and you set up shares so everyone in the house can use it, it’s self-hosted storage. If you set up an iCloud account its not. If you rent vps, manage firewalls and reverse proxies and host your stuff there it’s selfhosting. If you use digital ocean or aws and do it for yourself its selfhosting. Saas isnt self hosting