Yup, the expansion tank has several purposes, the biggie is of course, to keep the tank from flexing when it heats a cold tank up… but it also helps prevent that cold blast of water in the shower when someone flushes the toilet, it reduces hammering noises in the home when devices open and close. It really helps the plumbing system survive.Same. That's why my water heater's up to about 1994 code though, lol. What's an expansion tank?
I also install a mixing valve when I replace a tank. Set temp high over 140F, and adjust the water temp at the mixer. Doubles effective tank capacity, and removes legionaries disease concerns.