How to distinguish "use" claims from "product" claims?

The link pointed to in the question does not cover the case the question thinks it covers. The example in the question is not a "use" claim even though that word appears. As pointed out in the WIPO site "the use of substance X as an insecticide" is taken to be a method claim - a way of using. That is the claim is to a series of steps. In the question we have "a compound for use as a medicine" - that is a claim to a compound and the "for use as" tells us what one might do with it but that does not change the fact that the claim is to "a compound" - a thing.

Patents for doing a specific thing with a compound are method or process claims - " (a) calculate a dose of the compound and (b) administer a dose to a patient with X disorder.

The second example is clearly a claim to a thing, not a use. "A coating" is a thing. The rest of the sentence tells us how the coating is made. A claim - "A method of making a coating (a) get compound X, (b) crush it into a powder (c) dissolve it in oil . . . " is a method to make a coating. Another claim might be a method of applying a coating.