The main importance is that em fields allow energy to be stored within them through the process of induction and then propagated over vast distances using the dielectric and magnetic properties of materials (free space being one). read more
Electromagnetic Radiation - Electromagnetic radiation is a collection of electromagnetic waves traveling in vacuum or in matter. The energy radiated by the electromagnetic waves is called electromagnetic radiation energy. read more
Thermal energy is a form of radiation, and thus it's electromagnetic. Our bodies produce it, and materials like wood contain energy stored in it. I'd say electromagnetic radiation is extremely important. read more
The video and text below describe some of the qualities and uses of different waves on the electromagnetic spectrum. read more