You don't use classes only to get RAII. They are also useful when you have data with invariants, which the constructor establishes. And of course, if you want to use private data.
there's many ways to implement private data. if you prefer non member functions, a class is a bunch of extra keystrokes to achieve the same as the old fashioned C private data.
if you prefer non member functions to member functions, your private data becomes a global variable or struct in a file, and the private data is not accessible by getter/setter functions that are externalised.
Unless you're a fan of `friend` keyword ;)
however, it requires less keystrokes to implement private data in C, than it does to create a class to store private data.
therefore it's questionable, if you are preferring non member non friend functions, whether you should use classes when you want private data.
i refute the idea that private data is a reason to use classes, if you are preferring non member non friend functions as advocated by Stroustrup, Meyers and Stepanov.
as i said already
> There's very little reason for class members unless you want inheritance or polymorphism.