For what statistical analyses can you determine an R-Squared?
Any function can have the “fit” of the actual data assessed by an R-squared calculation after linearization.
“Regression” statistics are useful to show how close your approximation is to the actual data.
Do NOT use them as a justification for acceptance, but rather as a warning of the degree of inherent error represented by the linearized function. It is also extremely important to remember that interpolation includes the inherent error, but extrapolation (prediction) from a linear regression increases error dramatically as it moves further away from the actual data set.