And they may convince others to join App.net. Granted that many people will avoid App.net just because you have to pay for it and common internet guy will never realize what Twitter is doing. Still, if even top 10-20% of people who I follow go to App.net, I will follow!
Personally, I'm sick of being sold to. Ad-supported is not the only business model in town and I'm not sure when using an ad-supported service over a paid one became a virtue. If this makes me "rich", ok.
App.net is just proof that at least a few people agree with me.
I do think it's an exaggeration to say that app.net caters to the rich, but I can guarantee you that the demographics skew much more upper class, between being an app that is charged for and a service that mostly has interested hackers (who, nowadays, tend to be an affluent bunch, for better or worse).
Edit: Also, the value of a service like TV is something determined by the individual end-user. I don't think TV is more valuable than Twitter for everyone.
It sucks that Twitter is blocking cool development like this, but they've managed to become "a place where people are" (which is no easy task) and it's a mistake to underestimate that value.