In a statement to IGN, PlayStation says, “Globally, we are moving from PlayStation Now Gift cards to focus on our current cash denomination PlayStation gift cards, which can be redeemed for PlayStation Now.”.
There’s a chance that both of these are true, and that Sony plans to offer a unified retail gift card (I imagine there are folks who mistakenly purchase a PS Now gift card when they wanted a PS Plus gift card) as well as make way for this new online service.