Well, i've decided to check the 6* list, and apparently, while 20 DC are a lot common, there are very few who have B speed. As a matter of fact, only one, Phileas, is a common pack drop, while all others are LE units.
To be honest, i'd only trade/sell her if you don't need one with her speed and DC on your team, or if you were able to sell her, buy Phileas and still get profit. Check the market and see your options.
Ofc, don't forget that she's a reference to FMA. Her counterpart in equal name on the series has a knack for alchemy just like Fanta's version (though she has a completely different look).