I have to agree with you. For me this is the only purpose of the subchain. All the other points don't make much sense to me either and look like some trivial things that are inherent to all coins working with blockchain. But it is a very useful purpose because in combination with encryption it is impossible to track transactions due to the extra decoupling via a large pool where everything comes in and everything leaves again. The only thing that is needed now is a lot of traffic and then tracking will be impossible. You can imagine if there is only 1 transaction happening every 30 minutes, then nothing can be done to hide sender and receiver. Well, at least that is how I see it but I am not an expert in the matter.