There are two methods of transferring points. You can simply transfer points into your FF account. And then use the miles to get your award flight yourself. Or you could use MR's flight finder program and transfer points into miles, and then use MR's site to find and book your flights.
Aside from transferring your points from MR to your FF account, you can also "pay with points". That means that you simply use points to book your flights on American Express OPEN travel site. When you redeem points this way, 100 points gets you $1 in value.
The key differentiator of this card is the ability to earn triple points when you book airline tickets with the card. So it makes a great compliment or a replacement for some of their partner affinity cards.
For partners like Virgin Atlantic and America, Hawaiian and British Airways, their affinity card also allows you to earn triple points. So while there is less of an advantage of, MR occasionally has promotions where you can earn extra bonus points for simply transferring them to a partner airline. For example, British Airways is now having a 40% bonus if you transfer MR points into your Avios account.
For airline partners like Delta, it makes sense to compliment whatever Delta credit card you have with this one because you can earn triple miles. Or if you are a Kris Flyer member and live in the US, this is the only card which allows you to earn what is effectively Krisflyer points.