I went from mastery 5 to mastery 7 BBtrox in 5 games AmA

Do you think masteries are an indication of anything?

So if a g5 player first timed a champ in norms vs b5 their s+ is worth more than a challenger player that b+ vs other challenger? The g5 kniws the champ more? Or if a b5 gets an s+ in ranked playing full attack speed eve vs other b5s they know the game pretty decently since they beat other clueless players to a degree to warrant an s?