It's very unlikely that Google employees are going to be representative of Google's users as a whole (just look at the startups building niche products for Bay

It's very unlikely that Google employees are going to be representative of Google's users as a whole (just look at the startups building niche products for Bay Area techies). Ditto if you only looked at data of users that opted in (maybe they're highly unrepresentative). That means the heuristics/models that get built would be a worse fit for you, as a user, although it sounds like that's a tradeoff that you'd like.