I think the fun/hobbyist/urbanist answer is that people just like to know facts about where they live, I've spent hours now looking up different places' data. The more commercial answer if I were pitching this as a product is that 'who lives within X minutes of this point' is a big question in CRE site selection etc if e.g. you're deciding where to expand a franchise. The walk-time version is more of a fun demo of the engine than anything else.

Thanks for the feedback! The site (and I suppose this post) doesn't really do much to answer "what's the point?"