Those are both valid reasons to use both languages. The "only" (whether true or not) is what the argument hinges on. It is roughly the same as saying that the only advantage of X is that it is popular, but Y is also popular and has additional advantages, therefore, Y is better than X. That is a valid argument, whether the premises are true or not.

I do not disagree but if you are going to say that "X" is only used because of "Y", maybe if you are pitching "Z" instead of "X" do not start with the "Y" :)

Agree to disagree. He's setting up the argument that Z is strictly better than X.