Giving away open weight models, if you dismiss altruism as a motivation from the outset, is a way to salt the earth while at the same time building mindshare.

It makes it harder to extract decent margins from models at or below the quality of the open models, and so makes it harder both for new entrants and for any existing providers that are depending on cheaper models for revenue. At the same time you make people comfortable with your product.

It's the IP version of dumping products below cost if you're capital rich and want to winnow down the competitive field while "buying" customers.