By itself it's not a tell but combined with all else it's hard to pass by. Author's other article from 2025 has less than half the dashes and it's the same length
So we're actually witnessing in real time that he was slowly learning where to use emdashes? That's sort of hilarious.
How would the rise of dash usage in LLMs have arised if a significant portion of non-LLM writers weren't inclined to take them up and make them more common? The only explanation I see is that they are common in training materials we don't as commonly consume as website visitors.