Seems to me "micropayment channels" is somewhat of a misnomer. I belive the whole idea behind micropayments is to allow small payments for random publishers with which you don't have or need to maintain a relationship. Think random browsing, some pages costing 5c to view. At current fee levels the bitcoin network is perfectly adequate for this, although if everybody would do it the block limit will be hit and the fee would increase.

This is a trust-free incremental settlement system and does not really solve the core micropayments problem: fast and cheap transaction to random publishers. You will tell me someone can use this system to implement micropayments that publishers can leverage, and the user needs to do a single setup transaction with that centralized system. But in that case I really don't see Bitcoin's edge. Paypal could cover that market much better since they are better positioned in terms of market and mind share. Publishers care about their 5c and will implement the system that brings home the bacon, regardless of what currency it uses in the background.

(There are of course applications for this as explained in the thread, but "micropayments" ain't it).