Are type definitions for npm packages required only on developer machine?

As I understand, the type definition modules (for npm packages) provide intellisense for developers so that they don't have to guess parameter types when calling library methods. For example, these modules are very useful in my typescript project when I consume third party libraries (along with their type definition modules) in my vscode editor.

1. Is this the only purpose (i.e. provide intellisense) in for type definition modules?
2. If the answer is yes, then they should not be required on build servers and production machines. Is this true?

via Raghu