Sort of, but not really. A URL shortner has nothing else to do but lookup a central database and resolve a short URL into a long one. The short URL is more friendly for some formats, which is to the end user's benefit.

A QR code already encodes a URL. It can already be decoded and opened on your client with no other help or services.

The Tag equivalent sounds like a URL shortener in that it looks up a code in a central database and converts one to another, but the Tag is not shorter. It is not done for the end user's benefit, it adds nothing for the end user, in fact it adds a slow WAN lookup and all the reliability issues that go with it. It adds a third party into your data exchange for someone elses benefit.

It's more like a MITM attack on your transaction than a URL shortener.