I read this excellent dive into the system of a Notion power user. Although I haven’t used the service, it made me realise how Notion is basically specialised personal databases: everything is either a task or a document. But tasks can be viewed as lists, in the context of projects, as Kannan boards, as calendars. Documents can be notes, they can be notebooks, they can be collections. They can all be tagged, providing another dimension for viewing. (This is in addition to support for arbitrary databases).
That is a powerful conceptual model. Evernote is strongly notebook-influenced; other info & media is merely embedded. Sheets are two-dimensional tables. Task managers are list-oriented. They are all part of a personal system but are single-purpose and disconnected.
Airtable is a true personal database but like Microsoft Access of old, it’s general-purpose and supports limited data types as values. While powerful too and flexible, it leaves too much heavy-lifting to those that want to use it to organise varied personal information.
As of 2020, Notion seems to have found the right balance between databases and specialised use-cases for CRUD.