While we no longer use hieroglyphics to communicate, who uses symbolic representations and why?

The hieroglyphs were an inspiration for the script of the Phoenicians who adapted it to suit their language, and later the Greeks adapted it from them and the Romans from the Greek: the script changed as it traveled to new countries and was applied to new languages.

If by symbolic representations you mean a logo-graphic script (one symbol per word) then Chinese and Japanese still uses such script - the script there developed for many centuries which added to its complexity.