I disagree. I think that Counterparty adds value to the Bitcoin platform. I envision BTC almost being like gold, not something that will ultimately be used everyday. I think a token built inside of Counterparty will be that everyday used token.
Its kind of like the internet, the original value of the internet was to transfer files from point A to point B. Then came: email, the browser, instant messaging, online shopping, social media, streaming, ext.....
This adds additional value to the Bitcoin blockchain thus making it more desirable to have.
But i do agree that the miners should work on useless algorithms, that is the best way to keep it just and fair, but building applications inside of that is just fantastic
I tend to think that proof-of-work must be inherently useless in order for it to function for this reason - otherwise, it's not 'work'.