So the NSF has to manage $9B in grants but with fewer people to do so. That $9B will probably be less well spent now. So we're risking mis-spending $9B in order to save less than $20MM in salaries. That would be a really stupid move if the motive really was to improve efficiency.
Except obviously the motive is to not efficiency. It's about ensuring loyalty and even deliberately breaking the government to justify later actions.