No, utility means usefulness. It does not simply imply usefulness. You're also wrong that Utility and Specialty are antonyms. They are not. There's actually a contradiction in logic in what you say. Utility and Specialty can't be antonyms if Utility can, by your words, imply usefulness that is apart from generalized usefulness.
I can provide a real-life example of utility, actually. Over the past couple weeks I've been writing a game engine for the purpose of hoping to use it in the Ludum Dare (create a game in 48 hours) contest, within this engine is a utility class:
https://dl.dropbox.com/u/84091534/Optional_T.hpp
This utility class has the specific purpose of acting as a way to return success or failure of a function along with data. It's extremely useful, but only in the specific area of being a function's return value, but regardless of it's speciality it's still a utility class. Not only that, but this utility class contains utility functions, which are useful functions that have an even more specialized use of dealing with the utility class. Note the lack of generalization in all this utility.
Again, Raptress was correct in her example and usage of utility.
Can't argue with that. :3