It's a bit like people using acronyms. It often takes more time to explain it's meaning and defeats the whole purpose of the acronym in the first place.
I agree that it doesn't make much sense to use them for text and general conversation. Andrea and I are just being "different".
I wanted to see about how many people can understand what they are and read them. (They're basically just barcodes).
The practicality that I see is in providing website addresses and other contact info. Sure, you can print it out on a business card or ad (and you should), but if you can save the recipient the time and potential mistakes entering in a name, address, email, website, phone number, or whatever, and transfer all that information in less than a second.... that seems handy to me. Imagine if checkout clerks had to enter the product code by hand for each item you're buying.
Of course if nobody uses them, it's a moot point.