They're both "improving the world" by some standard, but not quite in the same way. There's nothing wrong with for-profit services, and plenty of "for profit stuff" absolutely makes the world better.

BUT... as technologists / hackers and people with (presumably) a broader vision, I think the onus is on us to prefer and to advocate for services which are "open" or "free" / "libre" (without getting too deeply into the definitions of "open" and/or "free" here).

I would say that it would be wrong to stay that Google Maps doesn't make the world a better place, but I'd also agree with your general sentiment and say let's do all we can to promote OpenStreetMap and the like.