Changing out regulator on my grill?

A few of my friends told me I needed to change my grill regulator to an adjustable one cause the stock one is at a really low psi, what are the advantages or disadvantages of putting one on there that I can make it put out a higher psi, does it really make a difference or does it not even matter to put out more psi. What about flow? Does that also play a part, I do know my grill doesnt get over bout 400 degrees with the one thats on there