It's most of all for communication all over the world that the metric is used in American science, but easier to use, well there's more logic behind it than the imperial system (which is what the US uses) which makes calculations easier, not to mention that the metric goes further than the meter alone, since grams, liters and many more measuring units are part of the metric and they have been set up with relation to each other. Like 1 liter of water is 1 cubic decimeter of water. The the gram has also been set up in a similar way. And basically that goes for all units in the metric. And many mathematical formulas set up for physics could that way be related to each other easily. But communication to the rest of the world is likely the prime reason, which is by the way also why all organs in the human body have Latin names so doctors in the US will always understand what a Chinese doctor is talking about and vice versa. And Latin names for plants and animals is for the same reason.