The use is a bit limited since we don't have too many plugins developed for the application yet. For the moment you may do this with regular barcodes (1D):
- Look them up on the web to see if any other stores have them in stock for a lower price. Currently this is only possible through search engines, but we (or other developers) will try to scrape this information from shops like for instance Amazon automatically.
- Share your opinion using Informed Individual (alpha).
- Get others' opinions using Informed Individual (alpha).
With QR codes and datamatrix codes:
- See what the code contains.
- Open it up in the browser if it is an URL.
- Add a contact if it's a VCard (probably in the next version)
+ more to come

The reason one would often like to find out what the product really is (as in it's full name) could be to do more searches for info about the product without having to type it in manually. It's just a way of doing things a bit faster and making it more convenient