Layaway is a different scheme: you pay down the price of a purchase in installments, and receive the item after the last payment. The layaway agreements that I'm aware of don't charge interest.
These schemes are VC-ified installment loans, which operate on the opposite model: you receive the purchase up front, and pay it down over time including interest payments.
They're arguably better on a strictly economic scale, since they give consumers the liquidity to make purchases that they'd like to make (and can actually afford, just not all at once.) They're arguably worse on a social scale, since installment loans are a form of cheap credit that people get addicted to, and are comparatively unregulated.