She can't manipulate every element. Should have explained that better perhaps. She can only manipulate the molecules of whatever explosive she is currently using. If she is planting something like a mine, she can only manipulated and plant an identical mine. If she wants to switch to making frags, she has to detonate the mines then give her body time to switch to the proper materials needed to make drag grenades. But she needs a sample of the needed materials to kick start the biological process. 

The suit is needed for a number of reasons. Unless you want her to be immune to every explosive-related explosion, she needs protection from her own power. She is a walking bomb with all of these chemicals surging around in her system, so it is possible for a wayward static shock or flame could ignite her. She has a certain degree of control, but she cannot override nature with the way I built her. The glowing nodes also give her a way to carry a few samples on her person, since they are needed to get her body to produce what she needs. If you want her to be a walking bomb that can go off whenever I'd like, then I can do that too.