OO, constants, exceptions, stronger typing e.g. templates and associated libraries of containers, booleans, references, new operator, don't have to decl every local var at a top of function etc. For many of us, C++ was a dramatically nicer experience for building very large code bases.

There are "C programmers" who are really using "C++ in C style" and don't realise what C++ brought to the table. Some C++ features have now been included into C.