I am not into active trading and do not use this feature often even though I've been aware of it. I occasionally buy of a certain amount of Bitcoin to add to my stash and when I do, I quickly check around the different sites I'm registered on for the variations to the market price and also the trading volume.
It would be very invaluable to day traders who would want to take advantage of the difference in prices to make profits.
OP provides a good tool for people who have not yet known about the site but when you want to do inter-exchange tradings by taking advantage of price gap of bitcoin over exchanges, there are some factors to consider further.
- Volume on input and output exchanges: To make sure that you will have good prices to buy and sell with your intended money.
- Reputation of exchanges you want to use for inter-exchange tradings.
- Don't store your bitcoin on any exchange after buying it. If you store your bitcoin on exchanges, it should be a very small part of your capital. You should never totally rely on exchanges' reliability and their responses or compensations for customers if there are something seriously wrong with their platforms (hacks, ie.)