Curiosity. It began while trying to play around with programming, and finding a lot of talk and resources about Linux, and then trying it. 3 broken Debian installations just for messing around, then Ubuntu as a more permanent install, all of this alongside Windows.

Then I began using less and less Windows until I just deleted the Windows partition because I needed more space.

It seems they consider themselves complimentary with OpenStreetMap, as stated on their FAQ https://overturemaps.org/resources/faq/#

Overture is a data-centric map project, not a community of individual map editors. Therefore, Overture is intended to be complementary to OSM. We combine OSM with other sources to produce new open map data sets. Overture data will be available for use by the OpenStreetMap community under compatible open data licenses. Overture members are encouraged to contribute to OSM directly.

I don’t know a lot about any of both projects, but it seems fair.