Everyday possibilities for use
A person on a 1850 calorie a day diet will be able to figure out their own meal plan, with foods they enjoy, and find out how much of what they can eat to meet that goal. I'd find that an attractive alternative to a canned plan from Weight Watchers or Jenny Craig.
Right now, I'd like to know if his engine could tell me how many Jelly Belly jelly beans could fit in a quart glass jar. When I search on Google, I find that people have asked the question before- on answerbag.com, among other places, but no one has posted an answer. Other matches on Google give ideas for formulas to find the answer- and there are answers for how many Jelly Bellys in an ounce- but a simple answer does not pop up.
If you ask how many Jelly Belly beans would fit inside the Statue of Liberty, you'll find Google doesn't seem to have a match with anyone who has asked the question before. (Strange mind, I know...) All of the matches in the first 100 choices that came up were mashups of pages. Of course, I had trouble trying to find data on what the interior volume of the Statue of Liberty is, so Wolfram|Alpha may not be able to answer either. I wonder, though, how many Jelly Belly beans would it take to fill the interior volume of the Great Pyramid at Giza?
Maybe the average person will find themselves using it most often for trivia. But sometimes they could find it handy to just ask “How much will it cost to ship a 16" x 20" x 6" package weighting 7.5 pounds from an address in zip code 10001 to 27 Main Street, in zip code 13607 by UPS ground? That sort of data is likely to end up in Wolfram|Alpha, and it means you don't need to go to the UPS site, enter the weight into a field, figure out if your package dimensions move you into a different class, and then have them calculate the answer.
It will let you do certain useful calculations in one easy step. If you are building your child a tree house, you can find out whether you should get half inch plywood or three quarter inch plywood to safely hold the weight of 5 100 pound kids. Not only that, it will probably give you a graph showing how much weight either thickness of plywood will hold.