"Opinions are pointless"
An opinion, by definition, is conjectural in nature, though we rarely present our opinions this way. Most are delivered as assertions pretending to factual knowledge: "Well in my humble opinion, (pause for anticipation) blah, blah, blah" as if it were God's honest truth. And when we say to someone "Well that's just your opinion", we're thinking "you don't know what you're talking about, so your opinion is pointless" – a viewpoint we're loath to turn on ourselves.
Were we to honor the conjectural nature of our opinion, wouldn't we deliver it in the form of a question, or preface it with "perhaps"? But as such it would no longer be an opinion. Thus opinions in general really are pointless.
In other words, if our intent in expressing opinions is to accurately describe reality, what's the point of pretending we know when we actually don't?
So is the statement "opinions are pointless" itself a pointless opinion? or rather an accurate description of reality? Our autocentric mind, cherishing the prerogative to opine, would ironically* settle on the former. Our ontocentric mind, delighted by irony, contemplates the latter.
* The irony of forming a presumably valid opinion that any particular statement is just an invalid opinion.