This can't be the explanation for everything, but I do know that once upon a time just the sheer source-code size of the types was annoying. You have to create a constructor, maybe a destructor, and there's all this syntax, and you have to label all the fields as private or public or protected and worry about how it fits into the inheritance hierarchy... and that all still applies in some languages. Even the dynamic scripting languages like Python that you'd think it would be easy tended to need an annoying and often 100% boilerplate __init__ function to initialize them. You couldn't really just get away with "class MyNewType(string): pass" in most cases.

But in many more modern languages, a "new type" is something the equivalent of

     type MyNewType string

or

     data PrimaryColor = Red | Green | Blue

and if that's all your language requires, you really shouldn't be afraid of creating new types. With such a small initial investment it doesn't take much for them to turn net positive.

You may need more, but I don't mind paying more to get more. I mind paying more just to tread water.

And I find they tend to very naturally accrete methods/functions (whatever the local thing is) that work on those types that pushes them even more positive fairly quickly. Plus if you've got a language with a halfway modern concept of source documentation you get a nice new thing you can document.