Nearly every electronic device sold at Walmart is a unique SKU sold nowhere else.

They have their own internal logistics and manufacturing specialist team that works with manufacturers to hit specific wholesale price targets that they demand to even consider carrying their products in store. They reduce the number of ports, features, included accessories, quality of materials, etc. to get the that specific price.

The manufacturers take a huge hit on their own profits from these... but in theory will make up for that with sheer sales quantity.

Requiring a Walmart account probably means some sort of kickback to Vizio, or other wholesale arrangement. And since these devices are usually unique SKUs that can't be sold elsewhere, they can receive differentiated software, have no risk of any sort of price matching, etc.