That's the beauty of gradually typed systems like sorbet. You only define types where you need to. Plus, it's really only one extra line of code per method. And that extra LOC gives you a lot.

So many of the production bugs I've encountered in my rails career (probably around 2/3rds) would immediately go away with a type system. Now, that's not to say that I won't encounter other issues, but type systems provide other benefits as well. Typescript annotations make JS seem pretty sane, and editor integrations like VSCode's support for TS is amazing. You get go-to-source functionality that isn't based on heuristics, compile-time error reporting as opposed to runtime error reporting.

Sure, it might not make sense in your situation. But every single job I've had in my career would've been much easier with a type system, and depending on how solid sorbet turns out to be, working in ruby might look quite a bit different in the next few years.