Interesting. I never start working on something without a rough idea of what I am working on, be that just researching something or a program; and uv makes it extremely easy to create a folder, and make it a project.
Could it be that you’re just used to separate environments causing so much pain that you avoid it unless you’re serious about what you’re doing?
If they are like me, they are just exploring different data, ideas and stuff - maybe without knowing/having descided if it will be a project. Many times it nice to use Python as a tool explore some data.