Notion clicked for me when I realised that everything is a "page with some attributes". Blocks are interesting at the engineering level, but as a user I found I was normally thinking at the level of pages.

Each page is some content (optional) with a set of arbitrary attributes of different types, e.g. date, string, number etc. When you create a table and populate it, you are creating a set of pages all of whom have the same attributes and the table is just a view of those pages. You can then create a calendar that's a different way of presenting those same pages. You can also deal with those pages directly and put content in, and reference them from elsewhere.

It's a really simple data model, and it's pretty flexible. We built all our processes on Notion initially and then moved them off when they got to an appropriate scale. I'm glad the API exist now, because then that approach can be incremental rather than a wholesale move. All the ways of displaying things - tables, calendars etc. are just displaying collections of pages.