@mike-noble from my own admission of "play as much as possible" your analysis is correct (though I hope I don't get pummeled that much). I guess I just can't rationalize paying $20 to potentially play a single round.
One nit-picking detail about your model, there are only five vintage trials Thursday not seven. So it's $100 for 5-10 rounds (assuming it's impossible to get to round 3 and still register for every event).
Last year had Four 5-round Swiss events, and you could easily register and play in two to their entirety for $60.
There was a mechanic in the Pokemon TCG called "Ace Trainer." There was about 20 cards with a special border and the text axe trainer on them. Any deck was only allowed to play a single Ace Trainer card. It's kinda like a super restricted list because you have to choose one over the other.