The Queen herself sometimes produces fireworks, mainly to amuse herself and to show those hoity-toity wizards she can do it too and better. There have been a few incidents of sprites overdoing their own skills trying to produce fireworks rather than wait for their betters to do better. It's easy to tell when this happens. Half a village usually gets burned down and those villagers made homeless tend to take out their own punishment on passing sprites if government officials can't get there first and make the right promises. (The government officials get put in the stocks if they're late with delivering said promises. There are many who feel this system should come to Earth).
Eileen likes producing fireworks and does so when on her own at home. She likes to see it as keeping her hands in. She also relishes taking those too noisy fireworks someone sets up to go off at awkward moments and then fire them at the offender to see how they like being startled. They generally don't. She rarely has to repeat her actions here.