What's the point?

What's your point?

Why say it if its value is debatable?

Because those values are yours, even though someone makes by definition an equally good point?
Isn't it way more interesting to find out why that person doesn't have the same opinion as you? Yours is certainly based.
Why not take your based opinion as opposition to someone else's statement?
Will it come across as negative or positive criticism? Will you work towards a solution or to another problem?
Is it ok for someone to criticize your criticism or does that devalue the original conversation by stepping into a new discussion?