The problem with this is their false matches. For example I looked up cffi (C foreign function interface) library. They decided to add a stock ticker of the same letters despite me never clicking on any stock links.
Any lookups of other things give the same results, such as looking up news stories (eg a plane crash starts tracking flights of the same number) or how many calories there are in a McDonalds burger (starts showing nearest locations). I don't remember the example now but I've had it decide other searches are really for sports teams. (Annoyingly they also don't consider Formula 1 a sport.)
The biggest problem is the functionality is non-deterministic. You can't be sure if a card will appear for flights (eg you look one up you expect to meet tomorrow), and you get unintended junk at other times.
The reason is that Google are taking a superficial approach, almost just doing string matching. They aren't going deeper and figuring out more context (eg did I mean a stock, which day do I care about for a flight, is there any chance I'm looking for a McDonalds versus looking at corporate financials).