[ollysb]

It's a marginal overhead and it also has the benefit of encouraging clear naming. Autocomplete is convenient but also removes some of the cost of poor naming. This is fine when you're writing code (the autocomplete just kicks in and you search for a method that seems about right) but it does nothing for the readability of your code.

[JamesBarney]

I would argue that readability and writability of class members are not the same. Many time verbosity will improve the readability but hurt the writability of the code, and auto-complete reduce the cost of this verbosity.