[jQuery] do I need to use var $var = "something"

[jQuery] do I need to use var $var = "something"


I've seen jQuery developers use the following syntax when declaring
variables. Does the $ character help in any way? Does it do anything
or is it mostly just for convenience.
For example is this:
var paras = $("p");
better than this:
var $paras = $("p");
thanks