It’s like business and a hostile takeover
Given that we have a huge and lawless branch of the government (administrative) that would likely subvert any orders Trump gives it and continue doing as it chooses in others, a clear “you do what I say or you’re out” and “a lot of you will be cut anyway” message helps prevent years of confusion, deliberate subversion and federal departments refusing to help citizens while blaming Trump for it.
The budget debates where Obama’s first step was closing off DC tourist attractions comes to mind.