We don't need a lot of stuff. But if you have the means why not.
It's easy to say get in better shape. But at a certain age that will never work. Absolutely no way my father pushing 80 is gonna get in better shape next year as he is this year. Ounces add up. Shave it off the action, scope, stock, and all the stuff you can allowing you to have it in places you can't.
Again for $500 more why not. Especially for a sheep gun. Everything else equal even being in shape the Ti action is gonna be better for weight and carrying.
I have two twin ultra lights one short action one long 6.5 man bun and a 30 Sherman.
For those two I definitely think it was worth it. I have one more build on my list to try and make an even lighter rifle for 500 yards and under. I even have ti action screws cut for mine. Do I need them nope but part of the fun is the build and being different. So if you are even thinking of one go for it.