Say you have an orderbook which updates every 1ms, with 100 orders/sec. Then you have a second orderbook with an update of 100ms. The second OB tracks the first. Anyone trading in the second OB will basically lose money if he is a market taker (i.e. crosses the spread). An example: a couple years ago a bank made a market of options on a future. They were not very sophisticated and quoted a price with a 15 second delay, while the underlying had a new quote every second. A trader noticed this and scalped the bank for a couple of hundred thousand $. Then they saw somebody made a lot of profit against them, and they stopped trading with him. This kind of thing goes on in financial markets all the time on different time scales. For a liquidity taker (the buy side) trading in a such a swap market is a losing proposition. It mostly leads to transfer of wealth to the liquidity provider. If the taker only transacts once a month, he doesn't care he had 1% of fees in terms of a spread. If he transacts 100 / day, he will accumulate losses quickly and go out of business. You need market makers for a market to function, to minimize the costs. And they have different incentives. In many markets market makers get money from the exchange to provide quotes.

A very interesting use case for me would be exotic derivatives, which can be transacted with between countries, i.e. a market where transactions are very difficult and don't very often, or transactions in countries which don't even have stock markets. Say establishing a kind of a stock market in rural village in Africa. I believe something like this will happen. I certainly do hope we will have an alternative system in place in case the current one breaks down.