I’m in agreement with you here. The biggest issue is that Zer0 allows you to play CV without investing into the older self-harm deck design which was notably more focused and weaker. I think Zer0 is an efficient card, but hardly one worth restricting/banning on its own. Anarch already has a ton of existing draw options and is still perfectly competitive without it.
The self harm deck is like D2D Making News. It’s a good meta call at times, but largely not relevant, consistent, or fast enough for most metas. It’s fine as a fun fringe strategy, but not a dominant one.
No sleight against you personally, but that’s a meaningful metric. Casual is full of a variety of decks and skill levels, and there are no stakes. How you play against a PE on Jnet is very different from how you’ll play against it when you’re in the 6th round of swiss trying to fight your way into a cut.