Sure if I could buy these items for less than I would in fiat (I could replace the sats I use to by the goods)

The issue with this is almost all the sellers costs will be in fiat so they need fiat liquidity either via credit (which can't be infinite and has a cost) or by selling a portion of the Bitcoin they receive. How much of a discount can they offer to be competitive with big players like Amazon just to retain a small amount of Bitcoin and arb melting fiat.

I much prefer this business model in a service industry business. Say I offer home HVAC services. I have healthy margins, so I can charge in Bitcoin and undercut my competition on price. Capturing a smaller margin which I would be able to retain in Bitcoin after paying all expenses but the Bitcoin grows in value over time. So basically I am using Bitcoin's presumed appreciation as a competitive advantage.

I was planning to do this as a test with a window washing business this summer but I got working on other things and never did it.