The same goes for E=mc². It is assumed to be correct but it has not been proven beyond doubt. Not disproven either, however. It's a bit like religion: a matter of belief. I'm an Einsteinian atheist
The different formulas are because you use lbs. If you use kg instead, it becomes the smooth and simple formula above. But why would the universe use Terran SI-units? That's what raises my suspicions. The formula is just too smooth in my opinion. The universe tends to be more complicated. Still, it's only my personal opinion and as I said, everyone is entitled to his or her own views. Time will perhaps tell who was a bit closer to the truth than the others![]()
I get what you mean with Einsteinian atheist, but I think you actually mean an A-Einsteinian. Otherwise you would be a follower of Einstein who doesn't belief in gods!

The other thing with the formula.... who cares if the numbers we use to define the placeholders in that formular are smooth or not.
That's precisely why we use E and m and c as a shorthand description of Energy, Mass and Lightspeed.
The numbers we use to calculate the equation are meaningless and arbitrary really.
They just belong to a commonly agreed number system so everybody arrives at the same conclusion.
As long as the results reflect reality, no matter how you label things, the equation is correct.