The limit on the number of projects students can store on my server is intended to get students to delete projects once they are no longer working on them - this is intentional, as a way of helping me keep the running costs for the site under control.
To be clear - there is no limit on the number of projects students can create. I want students to create as many projects as they'd like. But they do need to delete projects once they've finished with them. Allowing more than one current project at a time is only there to allow for a little overlap as students move from one project to the next, not a way to store many projects for long periods of time.
The motivation for this is to help me manage the hosting costs for the site - it's how I can afford to make the site available for free and without any adverts while still running it on a shoestring budget. There are many hundreds-of-thousands of projects created each month. The storage costs for this on aggregate is significant. If I didn't have an incentive for people to delete projects once they've finished working on them, the resulting storage costs in keeping the training data around would increase exponentially and I'd not be able to provide the site as I currently do.
Note that if you store the projects on your own computer (described in the tool as “In your web browser”) then I have no need to limit the number of projects at all, as it is your own storage you’re using.
Kind regards
D