A transaction involves exchanging something (usually a currency) for something else. What you say is that with bitcoin you have proof and irreversibility of payment but the transaction can still go wrong because payment is only one end of the deal. And when the transaction goes wrong you probably wouldn't want a form of payment that is irreversible.
I am not making a claim of whether or not you want irreversible transactions or that they are somehow inherently better than reversible ones.
I am simply pointing out that USD != bitcoin, so the Tesla-driving-cash example is a fundamentally different thing than a bitcoin transaction.
It's like saying "Jeez, it took THAT MUCH energy to get to the Moon? I can drive around the earth a thousand times with that much energy!"
Yes. You can do that. It might be smarter and better for you to do that. But you won't be on the Moon at the end, and there's no way for you to get there unless you take a spaceship.
In this example cars = money, and spaceships = bitcoin.
