One underrated perk of string interpolation: it arguably simplifies type checking.
If you have a format() function you need to support variadic functions and even format specifiers in the type system.
miniblog.
Related Posts
I've added basic sum types to my programming language project, and it simplifies a bunch of stuff. Bool and Unit no longer need to be built-in types!
I'm now working on wrapped data, so I can implement Option :)
OCaml has several unusual design features that I've come to appreciate.
(1) Separating integer and float addition is really clear.
(2) No subtyping (everything is 'a or concrete) simplifies lots too.