The point of Glass isn't putting a powerful computer on your face (well, it's not the only point, anyway).
It's Google and its Sum-Of-All-Knowledge apps.
Who's gonna want a more powerful system if they can't use Google's maps on it?
You nailed it, but I think you only scratched the surface.
What knowledge does Google have, anyway? You mentioned Google Maps, and yes, that is a good one.
But what about all the information they can glean from GMail? Yes, we've been lead to believe Google provides e-mail in exchange for targeted advertisements.
I would posit it goes further than that. Consider all the photographs that have been sent from (and to) GMail. With some facial recognition software and rudimentary text analysis, I suspect Google may already know your name and what you look like.
Ponder on that for a bit.
Consider this e-mail message: "Hey there Jim! How's it going? Here are some pics of me and the wife on vacation. Wish you were here!! --Steve"
Do some feature analysis on the photos, tag them with links to Steve's info, and add it to their dataset.
Now consider, also, all the pictures that have been uploaded to photo sharing sites, and which Google dutifully spiders and indexes. Given Google's computational and indexing capabilities, I suspect those photos have also been tagged with links to people's real names, addresses, phone numbers, etc.
THIS is where Google has the advantage over all the other Glass-alikes. Google has a much larger dataset from which it can identify someone or something. The other glasses may have better technical specifications, but they don't have access to all that data.