Yes, your three advantages hold, but check that: Think of the mempool as a waiting room. The attack keeps yanking Bob’s payout transaction out of it so it never confirms in time.
The two versions differ in how Mallory yanks it.
The original kills a different transaction that Bob’s depends on, so his falls out on its own.
The alternative just directly overwrites Bob’s transaction.
The alternative wins mainly on cost: to kick a transaction out you must pay a higher fee than what you’re replacing, and in the alternative Mallory is overwriting her own cheap transaction — so it’s cheap every time. In the original she’s stuck beating a fee she doesn’t control.
Since she repeats this cycle many times, cheap-per-repeat matters a lot. It also needs less setup and is more reliable, since everything belongs to her.
The original’s only real upside: it can make the bad transaction look juicy to miners while it sits there, without costing more to remove later.
Bottom line: the alternative is better in practice; the original is just the clearest way to explain the attack.
