I suppose. "Made for iPod" is a special branding program by Apple. Apple iPod has the biggest market share therefore you will see a lot of products made specifically for iPod, including speakers. Usually these speakers also have an aux input for non-iPods. Apple gets money from participating manufacturers and in turn they sell their products because they're made for iPod.

I'm not an expert on sound quality. From my perspective, I get better sound and volume when my iPod is dock connected than when it is connected through the headphone jack.

You should get better sound quality with a mini audio system in conjunction with a dock, such as the DLO HomeDock.