It is simply at a different level, there are account level projects and repository level projects.
Say I have projects that i want build for my portfolio, say todolist. In my account I would have a project for what it is that i need to do get that underway (hire staff, make the scaffolding for the project with create-react-app, buy a computer etc). Ok now that's done... time to start adding features to the repo that you have made... so make a project in the repo... maybe the todolist needs a list? Card for that, install a test suite? All the features i (might) put into the project for a repo... the account level is before you create a repo (at least in my world).