[NativeNewYorker]

A belief in the Theory of Evolution is as fundamental to a doctor as being able to ride a motorcycle. Useful, sure. Clinically useful, not really.

Is a belief in G-d "useful" but necessary to, for example, celebrate Mass? Or is command of Latin and ritual all that's necessary?

[Dataman]

Is a belief in G-d "useful" but necessary to, for example, celebrate Mass? Or is command of Latin and ritual all that's necessary?

DK's analogy is better. Once again, here is why your analogy does not work:

Evolution and biology are two different disciplines. Claiming otherwise does not change that fact. Evolution depends on biology but biology does not depend on evolution.

Evolution is not science. Claiming otherwise does nothing to change that fact. It is an attempt, employing many flawed presuppositions, to explain the origin of life. That's all it is: an attempt to explain.

[Dark Knight]

Is a belief in G-d "useful" but necessary to, for example, celebrate Mass? Or is command of Latin and ritual all that's necessary?

Yes, a belief in G-d is "useful" in the exercise of one's faith. If you are saying the evolution is taken on faith, I agree.

DK