Energy in physics feels analogous to money in economics. Is a manmade medium of exchange used for convenience. It is the exchange medium between measureable physical states/things.
Is energy is real in the same way money is? An incredibly useful accounting trick that is used so frequently it feels fundamental, but really it’s just a mathmatical convenience?
Small aside: From this perspective ‘conservatipn of energy’ is a redundant statement. Of course energy must be conserved or else the equations are wrong. The definition of energy is it’s conservation.
A medium of exchange for force.
A photon of a certain wavelength imparts a known force when colliding with an electron. That force propels the electron to a higher orbital.
And how does the “manmade” tie into that? Did we make the photons? Exert the force or did we do something that brought force into existence?