Solid idea and the controls work. I felt safer using a merchant-locked card at a site I didn’t fully trust, and setting a total cap was easy. Still, the inability to fund with a credit card means no rewards, and one merchant kept failing until I raised the per-transaction limit. I left feeling protected but slightly boxed in. It’s great for budgeting and stopping unwanted renewals, but you do bump into quirks with payment methods now and then.