While your story here may not be representative for other reasons, it is clearly irrelevant what protocol you used. You would have had exactly the same e-mail problems (I take it they are reputational in nature) if your mail was pushed over JSON over HTTP. They would just be a lot harder to debug.
And the connection limit your friend encountered on IRC would be just as relevant if it was a web chat over HTTP. In fact, they would be worse. If it should be taken as an argument for anything, it is clearly that one should not try to cram even functionality over one specific command protocol.