This looks like a "user first" approach which I, as a user, really dig. Don't forget that Google is likely losing out on adwords revenue as a result of this change.
Wolfram alpha tells the user how they interpreted your question, google doesn't. So how do you know google is giving you the right answer? Without search results, alternative answers are harder to get. Remember the 'how far is the sun' query ?
On the other hand:
1) this kind of query is not a big driver of Adwords revenue
2) the direct answer is cheaper to compute than a search of the web index
3) this result page is much smaller to generate, serve, load and render