As the article notes they are planning to invest 9 million euros in the transition, so they clearly don’t expect it to be “free of cost.” The difference is paying 15 million euros to license some proprietary American product, versus investing 9 million euros in the free software world.

Some people use it because it’s free, some because it’s open, and some simply because it’s not Windows nagging them. With every movement that gets popular you’ll have people that don’t join for the cause but because something in the movement aligns with them, we should allow those people to use the software without making this a purity thing, at the end of the day desktop Linux needs users, not zealots, first and foremost.

The fact that people can come in and put up with Linux in spite of not being here for the cause should be celebrated.

But that will convince nobody to also switch

According to this Interview from 2021 costs are ultimately expected to be roughly the same. Also it can be argued that having Support and security patches for the Software is more or less required by law if you intend to use it in (German) public Service.