Here's a good explainer–if Trump fires 50,000 government employees (and he may fire more), it will not only wreak economic havoc in the Washington, DC metro area, it should impair the ability of government to function competently.  That may be one of the points, of course, although I assume Trump's main motivation is to have the government populated with Trump loyalists.  But since "Trump loyalist" and "competent professional" are not categories that overlap a lot, this bodes ill for the quality of federal services.