If you're talking about government snooping, they most likely can aggregate information from different sources.

If you're talking about the nebulous "one company has all my information and may do something evil" argument, I still say that it doesn't matter. Email is by far the most sensitive thing most people do online, so if there was a real threat from a company having all that information, also having searches is not substantially worse.

Regardless, I still don't see a credible threat of harm from Google having this information that outweighs the actual threat of hacking.