@thibaultamartin Can I add something, as a non IT expert who loves Linux. I think the difficulty for non-technical users is far overestated, and the bullshit Windows pushes on non-technical users is far understated (let alone phones).
If someone shoves Mint or Ubuntu on a USB, guides Grandma through the process and the hardware gods are kind, then she need never see a command line again. If the salesman does that much, that's a linux user for life.