Why do you think neon is used in signs?
Because it's pretty..........
The say that the original large neon signs that adorned Las Vegas in the 1950's and 60's, literally stopped traffic, and encouraged people to come to Vegas to lose their money. The mixture of neon (and other gases) in gas discharge tubes allows very effective and eye-catching displays. And of course, the manufacture of the glass tubes to contain the gas is cheap.