Gödel's arithmetization of logic is one hell of a beautiful mathematical idea, up there with linear algebra or probability theory. One of its big selling points for me was how easily it solves the unexpected hanging paradox. (The simplest arithmetization of the judge's self-referential statement is a statement about numbers that can be shown to be self-contradictory.) It's also cool how it turns Russell's paradox into Gödel's theorem, Curry's paradox into Löb's theorem, etc. The connections to algorithms and computability theory are also neat (Gödel's idea of "effectively axiomatized system" is any computer program that can print sentences, which has just the right amount of generality and connects to the halting problem in the obvious way). To me arithmetization is simply the right approach to logic, which easily subsumes everything that makes sense and rejects everything that doesn't.