>Otherwise this is just making dev life easier on the cost of their users.
Not necessarily so, I'm expecting removal of dead code will enable faster delivery of new features, and also enable easier refactorings to make code more robust, because the dev team won't have to take unused features into consideration. The code we inherited is very complex and very brittle, so adding something often breaks something else and devs spend way too much time figuring out all the interdependencies. A major complaint is that the dev team doesn't deliver fast enough.
"I'm expecting removal of dead code will enable faster delivery of new features"
Well, for sure it does. Getting rid of bloat is always freeing energy - but only if it is really dead code. Otherwise you can introduce rare bugs, or break things in unexpected ways. And yes, sometimes the fastest way is to just try it out and see how things run. If it is not medical equipment, it might be fine even on a live system. It really depends on your project and users. But most users really like stability. Especially if they need that software at that moment, because they have deadlines as well.
It really depends how urgent those people need that something at that moment (and how much they paid for it).
Otherwise this is just making dev life easier on the cost of their users.
Before deleting code, why not check who would call that code and why? But yeah, that is also work. (And not always worth the effort)