Wrong, the core advantage to WA is that it relies on curated data. That you know it's from a verified source makes a world of a difference. That it can produce actual answers, not just averages or random tidbits, is essential.
Yeah, that's my main concern as well. That kind of curation just doesn't scale. There's a large body of people out there who can be leveraged, who spend their lives curating and optimizing data sources, especially in chemistry and biology.
The core flaw with Wolfram Alpha in my opinion is that it relies on curated data. Such data takes time to source, verify, and translate into the necessary target format.
I sincerely hope the same thing for Wolfram Alpha that I do with the Palm Pre: that it'll get the market leader off its ass and spur true competition.