What are the benefits of reorganizing the U.S. House of Representatives every 2 years?
The main benefit of having elections (and therefore possibly reorganizing to some degree) every two years is that it allows the House of Representatives to remain more closely aligned with public opinion.
When the Framers of the Constitution were working out the new system of government for the United States, they wanted at least part of the government to be very close to the people. They selected the House of Representatives to fill that role. The Framers, of course, wanted some degree of democracy in the new system. To get that democracy, they decided to have the House be elected every two years. This would mean that the entire House could change relatively quickly if public opinion changed. The Framers balanced this out with a Senate that would not change so rapidly and would therefore act as something of a brake on popular opinion.
The main advantage of having the House reorganize itself every two years, then, has to do with democracy. It allows the House to be more clearly controlled by public opinion than it would be if elections were held less often.