It’s not only
Both games’ boxed editions are being handled by publisher Merge Games, and both are currently only confirmed for an EU release. Further, both are free of DRM.
The Binding of Isaac ‘The Unholy Edition’ (read: boxed edition), comes with a DRM version of the game, a Steam gifting key, the game’s soundtrack, a poster and a 40 page ‘dev-zine’.
The Binding of Isaac The Unholy Edition is due on 16 March.
I like the box art…