On Mon, Aug 8, 2016 at 1:48 AM, Matthew Roberts <matthew@roberts.pm> wrote:

Not everyone who uses centralized exchanges are there to obtain the currency though. A large portion are speculators who need to be able to enter and exit complex positions in milliseconds and don't care about decentralization, security, and often even the asset that they're buying.

Centralized exchanges also allow for things like limit orders. You don't even have to be logged in and they can execute trades. This couldn't be done with channels.

Try telling everyone who currently uses Btc-e to go do their margin trading over lightning channels, for example.

Using channels and a centralized exchange gets many of the benefits of a distributed exchange.

The channel allows instant funding while allowing the customer to have full control over the funds. The customer could fund the channel and then move money to the exchange when needed.

Even margin account holders might like the fact that it is clear which funds are under their direct control and which funds are held by the exchange.

If they are using bitcoin funds as collateral for a margin trade, then inherently the exchange has to have control over those funds. A 2 of 3 system where the customer, exchange and a 3rd party arbitration agency holds keys might be acceptable to the exchange.