They won't be compensated too much though because Twitter has made auth tokens arbitrarily scarce. AFAIK they have a cap of 100,000 customers for the lifetime of the product which means they're limited to $2M in revenue on this (less Apple's fees, so $1.4M and any returns would most likely still count against tokens but offer no revenue). It's not super lucrative, if they hadn't already started when Twitter announced its plans I don't think they would have made it.
Thanks for this comment, it prompted me to read up more about Twitter's new policy for auth tokens. I had seen some headlines passing by, but didn't bother to read them. Anyway, then indeed it makes much sense for Tapbots to get the most out of relatively limited quantities.
I guess that this also makes a strong point for App.net: users won't be bothered with apps and growth of the third-party ecosystem isn't artificially restricted.