I find it interesting that Rovio is choosing to build its own payment system rather than use the options that Google is integrating into the Android platform.
I don't have a problem with granting these permissions to an app that I use that comes from a well known, trusted developer. Also, the features that require the permissions aren't used unless you actually make the decision to use them. So while the developers really should make sure they educate their users before taking their money, in the end it falls on the users to make the decision to buy.
For one thing, Google in app payments via carrier billing are not available yet. When it will be, I would not bet too many of the world's ~200 countries will be supported, just a few key markets. Same with Android Market itself, it works in just a tiny mnumber of countries: http://market.android.com/support/bin/answer.py?answer=13829...
It's not very surprising that they decided to do this, especially since it was first (and so far only) launched in Finland. I don't know about the rest of the world, but Finns are quite used to paying for things with their mobile phones. Giving your credit card number for a smart phone app or an online store does, however, not seem like a very safe thing to do for a lot of people not used to deal with these things. I'm not sure if those people use Android phones very much, but I am quite sure this will make it much more appealing for many to pay for the extra content.
I don't have a problem with granting these permissions to an app that I use that comes from a well known, trusted developer. Also, the features that require the permissions aren't used unless you actually make the decision to use them. So while the developers really should make sure they educate their users before taking their money, in the end it falls on the users to make the decision to buy.