I haven't financed furniture but my impression is that if your credit is decent that the cost of financing it is basically the same as paying cash.

Furniture is high margin, low volume so furniture retailers have an incentive to spread out cash-flow and get consumers to buy more expensive furniture than they would if paying all at once.

That said, I suspect if your rand the numbers you'd find that the overwhelming majority of furniture (by units sold) is bought cash from Walmart, Ikea and the like by people paying cash.