Ruby and the age of “I don’t care what type this variable is, it quacks like a duck!” is over and dead. Improvements to type systems have shown there is a better way to do software development.
So we're only left with personal opinion
You're not going to misuse an API that takes a Person or Cart, but mixing up two hashes cause you used two different strings as keys can happen easily.
(I do think dynamic typing is mostly fine, but I do wish ruby had optional static typing with some nice syntax instead of RBS)
This is more or less trivial to catch and fix, I'm just not sure a type system is worth it's weight for that kind of case.
I’m really excited about Sorbet getting behind the new RBS-inline comment syntax and the prospect of both runtime and static analysis as optional tools when needed.
Plus, Ruby has lots of easy ways for you to check typing, if you want to.