It's less about the wording than the information it conveys, that you respect someone enough to talk to them politely and make the effort.
If it's hard to see the difference, would it make sense if I made an analogy? Your girlfriend texts you "call me? :)" vs. "Call me."
One is clearly flirty and in a good mood and the other could be angry? upset? urgent? The extra punctuation conveys information about how that person feels.