It would provide very minor scratch protection by refreshing your oleophobic coating and making it slick, but like you mentioned, it won't protect from a real scratch.
There are some ceramic clear coatings for automotive paint that would probably provide stronger scratch resistance, but I'll tell you right now, they are DAMN expensive. $70+ an oz.
If you just want to redo/refresh your oleophobic coating, there are cheaper ways. Fusso makes a coating kit for tablets that will last you the lifetime of your phone and probably your next 2 devices as well.