EzekielRaiden
Follower of the Way
Why does "can provide magic power to others" equate to "actually a transcendental being worthy of devotion and reverence"?You can invent some loopholes, but if the god can consistently turn off magic of their priests, but not magic of other people, then that would be good enough by reasonable standards.
As far as I'm concerned, the high lords and ladies of the fey, the royalty and upper nobility among genies, the most powerful demons and devils, and a variety of other beings are perfectly capable of providing power--perhaps even in the form of daily spell access!--to those who act in their name. Granting spell slots is just another way of saying "they're powerful." Power alone does not a true deity make.
(And for my Jewel of the Desert setting, the servants of the being claimed to be the one monotheistic creator-of-everything explicitly recognize that there isn't any method which could definitively answer the question. Nobody has the ability to conclusively prove beyond all possible doubt that the One actually is the uncreated creator. It is, necessarily, a matter of evaluating the evidence available to you and making a choice. Based on other evidence, if the One truly is the creator of all things, They actually want it to be this way; They do not want herds of unthinking believers who see irrefutable proof and then disengage. Their servants claim They chose to create, and to include sapient creations, because They desire things which can only come from enthusiastic, active consent: to fill the tapestry of existence with each new perspective, each new thought and hope. That is why They forbid Their loyal servants from ever using their powers to coerce mortals, even for beneficial ends--because that very act of coercion is contrary to the purpose of existence.)