The distinction that matters is merchant of record, and it is a legal one rather than a technical one. With Stripe you are the seller and you owe tax in every jurisdiction you sell into; with Paddle, Paddle is the seller and owes it instead. For one person selling a product internationally, that difference is worth more than the fee.
Filed as evaluated, not used: relevant to the question of what a small software product costs to run, which is a question this garden keeps circling.