The resulting detonation is said to knock the deposits free. I guess the "fine spray" is to ensure you don't hydrolock the engine.
Would I do it? Not on your life. Why bother? Have you seen the piston tops of high mileage MB engines that have lived on modern no-lead fuels? Since the mid '80's, carbon build up has not been any kind of a problem on MB engines. Any I've seen apart have been pretty clean.
A very wise person once said "If it ain't broke, don't fix it." This would be one of those times to heed that advice.
1998 C230 "Black Betty"