I feel that Uber Ice Cream delivery can be a huge success. As long as they don't make it so that it is way to costly I think a lot of people will use it. A great example would be after a kids baseball game instead of having to try to get them all rides you could have it delivered.
I don't think it will be a success in the tradition way, I don't think many people will be ordering from their for their small familes, but I think it will be a hit for parties. If you order 10 or more ice creams you get your own ice cream truck to deliver it, I think many parents will do that for their children's parties.
Possibly the concept would work in a tropical or beach-like climate with a constant temperate of 80 plus degrees. In Chicago, the windy city, I do not foresee much of consumer base. Plus the terrible traffic for deliveries, and the rate of crime is currently at an all time high.
While a fabulous idea, I don't see the execution being successful. Uber will try this on Friday's only and people with bite ( no pun intended ). But on those sweltering hot days when even with the technology of ice, in comes your cup of slop. In theory, brilliant, practical, not so much.