EL Wire vs EL Panel, difference in voltage and frequency needed?
While EL wire tends to use phosphors, the EL displays that I am aware of typically use materials like GaAs.  Phosphors use ballistic transport and electron impact to impart the energy where as the semiconductor type devices have recombination of electrons and holes.

The semiconductor type panels will be more efficient (generation is less energetic) less scattering and reduction of energy before the light is emitted.