I looked at this site several years ago, but thought nothing of it. Then the other day I stumbled upon it again. It’s only appealing for the ability to buy hard-to-book tickets on obscurer airlines, particularly those in Russia, CIS and some other places. Naturally, a premium is charged. For example, you can see on Amadeus Best Fares that DXB-CGP-DAC with BG (on the 742) should on the 16th June is £77* - yet frustratingly you can't book it on the given link, suggesting you'd probably have to visit your local BG office to get that fare. Alternative Airlines charge £98.80 for that flight. The difference (£21.80) is, I suppose, offset by the saved money, time and effort of not having to visit your local BG office.
Just thought it might be of some help or relevance to anyone planning a trip on rarer, harder-to-book airlines.