Same product in furniture store existing in multiple dimensions:

End customer presentation - front-end how customers are interacting and configuring their product
Inventory tracking and 3PL - how ordered product is reflected in Admin panel in Orders and who is pushed to 3PL for dispatching a package so for example in one case Chair + Pillow is 2 SKU’s one for chair and another one for pillow, in another case when pillow is an integral part of chair the different color of the pillow with the same color of the chair would result in a dispatching of a specific SKU of a chair with that color of pillow…
Google Shopping Feed - this one is tricky because each combination of options should be presented as separate product there and whenever Google Shopping bot opening the page to perfrom offer conditions validation it should return to that bot exactly the price and details of that combination it was submitted there

Sell products as a "set of 2"

In furniture ecommerce cost of delivery is high enough to justify the "co-packing" of products. This way a concept where pair of chairs can be sold as a single SKU on the customer facing side, however need to be tracked on the Admin panel as a quantity of 2 for another mapped SKU.

Additional level of complexity comes into play when Google Shopping Feed expecting to fetch exact same PDP as it received into their database through a Channel integration.

For more use cases and general overview of headless commerce topic in general click here