When you say gene regulation you are really speaking of gene expression. The expression of different types of genes is important to the organisms survival. This expression determines or regulates the information in genes which controls how the genetic information is turned into various biological products.These regulatory mechanisms chiefly control the genes that regulate proteins.
The regulation of genes is critical because eukaryotes, prokaryotes, and viruses depend on it for adaptability. Another important fact as far as gene regulation goes is that in multicellular organism's the processes of cellular differentiation and morphogenesis depend on gene regulation to produce the various types of cells that they are capable of producing. Without the regulation of genes this production of cells would not be possible.