It probably doesn't hurt anything, but it certainly doesn't confer any benefits either. The stuff is just 5W oil. No mystery, and not that marvelous. Save your money and skip the too-good-to-be-true wonder products.
Heard of others using it in their aircraft. I had one exhaust valve stick twice before using MM Oil and not once since.
I've used this product for years...when I see how many pro's use it and heavy machine makers and repairers using it.. Caterpillar etc I was convinced this is a great additive..!
I use this stuff every year when winterizing gasoline outboard engines. It works great! Never had any issues. I tend to blend it with a few other products that minimize oxidation of the fuel, and run it for a good spell while fogging the engine. Added benefit, I use it around the house too.