Simple, they want Recursive Self Improvement and worry that git will be the bottleneck. So they are making source control as efficient as possible in preparation for that day.

From the first paragraph: "Claude is able to autonomously iterate on research loops, micro-optimize complex programs, and build new services from the ground up at a speed and scale we haven’t seen before. The bottleneck, now, is all of the developer infrastructure built for human scale: source control, builds, and CI."