Because if there isn't then come January 3rd there will be no House of Representatives and the Senate will only be two-thirds its normal size. Chuck Schumer will be Senate Majority Leader and the Democrats will select the President Pro Temp. He or she will then become president on January 20. That what you want?
Nope.
Still possible that we have entered uncharted territory here, and that everything we have known is about to change.
This is an excellent point, and people better think it over what they are saying.