Full Idea
The interest of Frege's Theorem is that it offers us an explanation of the fact that the numbers satisfy the Dedekind-Peano axioms.
Clarification
Frege's Theorem says arithmetic rests on one-one correspondence
Gist of Idea
Frege's Theorem explains why the numbers satisfy the Peano axioms
Source
Richard G. Heck (Cardinality, Counting and Equinumerosity [2000], 6)
Book Reference
-: 'Notre Dame Journal of Formal Logic' [-], p.204
A Reaction
He says 'explaining' does not make it more fundamental, since all proofs explain why their conclusions hold.