There are a significant number of weaknesses in cvs, especially for software like Postgresql that would benefit from reasonable version control, beginning with atomic commits and I won't bore you with other CVS oddities.
So git, WITHOUT changing from a CVS style workflow, is going to be much nicer for the project to use as their authoritative vc. So switching to git while keeping CVS workflow is not weird at all. It will improve results for the project.
Not adopting all gitisms at once is also not weird. Any larger organization moves slowly, rightly I think personally. They have an approach that works well. Let's wait a year for things to shake out before worrying about going with all the gitisms.
Credit also goes to the project for respecting the consensus that developed which was to switch to git without abandoning work styles. If you read the discussions, this was important to a number of committers and I think a good thing to respect. The value of the commiter I think outweighs adopting a specific ism of a specific tool.