But if I write code for a team, then in some places I will use explicit type annotations and variable names to aid people unfamiliar with the code to understand what's going on.
What you are saying is pretty much "it's easier when everyone only uses nails, because then all I have to bring is a hammer". I think it's good to use screws sometimes.
However, your second point I agree with. OOP vs. FP is a different story. This is about paradigms not about mere syntax. So here, a team must be aligned, which can be a challange when using Scala. It's not a language for corporate drones.