The left already rewrites the Constitution without the prescribed process. Do you want them to keep that advantage? Even Jefferson realized early on the danger of that power the Court of Supreme Whim seized early on. It's Dred Scott decision literally pushed the country into war killing over 620,000 Americans in the ensuing Republican-Democrat war.
The COS is the way to correct all these mistakes America has learned the hard way over the last 2 centuries. Remember 3/4's of the state houses have to amend anything that passes. It's a high hurtle to cross. Here is what actually happened at a simulated convention .