It's disruptive to the commons, doesn't add anything to knowledge of a model at this point, and it's way out of hand when people are not only engaging with the original and creating screenfuls to wade through before on-topic content, but now people are creating the thread before it exists to pattern-match on the engagement they see for the real thing. So now we have 2x.
It's often just a single root comment that you can collapse.
I find how svg drawing skills improve over time interesting. Very simple and very small datapoint. But I still find value in it.
Something seems off when I combine those premises.
You also make a key observation here: the root comment is fine and on-topic. The the replies spin off into nothing to do with the headline, but the example in the comment. Makes it really hard to critique with coming across as fun police.
Also, worth noting there's a distinction here, we're not in simonw's thread: we're in a brand new account's imitation of it.