It really comes down to preference for a character like this. You’re absolutely right that the simplistic shapes make it a good candidate for traditional polygon modeling. And if your poly workflow is more optimal than sculpting, you should do what’s optimal.
For me personally, I haven’t poly-modeled a character in years. Ever since I discovered digital sculpting I go straight into sculpt mode for any and all organic characters (followed by retopology if the character is meant to be rigged and animated). It’s just a far more intuitive way to shape organic forms for me, whether simple character like Melvin or complex anatomy.
Neither approach is better than the other for a character like this. Once an artist is proficient in both poly modeling and sculpting workflows, it comes down to choice and preference.
