Sure, for simple flows-of-control, GC buys you little and an RAII type approach is fine. But RAII really only works if lifecycle and ownership spans are reflected in the lexical structure of the code base. RAII relies on creation and cleanup happening within a block/lexical scope.

Unfortunately in the real C++ codebases I've had to work with, the flow of control is never so simple. Any correspondence between lexical scope and lifecycle is broken if the code uses exceptions, callbacks, any type of async, threads, etc.