Haven't tried Flitz on anything yet. Wouldn't be my first thought for blued guns--if it will make a rough feed ramp shiny, that means it's abrasive.
I am a huge fan of Renaissance Wax. Everything I have gets that if I don't know when I'll be shooting it next. Have a custom knife and several guns I haven't had the chance to use on over a year, they're prettier than I expect old surplus to be (even damascus, in the case of the knife), and not a spot of rust in constant Florida humidity.
Not as good as proper storage grease, but it's a lot prettier and you don't have to clean it off before you use the gun, if you make sure it's oiled. And, yes, my perception is that it's easier to clean after the next trip.
Basically, I'm a fan of using things for what they're designed or actually good for. Just takes research beforehand.