Compared to that, payment channels are a decentralized paradise.
It depends if you are trying to define a new cash medium or simply make an old one faster.
Payment channels do not redefine bitcoin and that fact is going to stick with it far more malignantly than Dash's instamine did with its fortunes.
There's no monetary medium you can't scale with payment channels and therein lies the problem - it's no better than an exchange in that respect.
If we are doing offchain txs through an exchange, the exchange can run away with toknormal's and alex's money. The payment channel can't. So it'd serve us better to do it in a payment channel.