Special Effects are an art of their own kind. They contain an element of danger, but can add to a film a reality and highlight that are essential. GCI/VFX is used more and more, but practical effects are still often more realistic - or sometimes cheaper. The first and most important aspect of SFX design is making the shoot safely.
Fireworks are a combination of pyrotechnics, choreography design and music. They can create an impressive show for large audiences with good cost effectivity. A well made fireworks show is an experience that no other audiovisual performance can rival. The Japanese insightfully call fireworks "fire flowers".