I mean it's a marketing thing mostly. It stems from the "adopt don't shop" motto (because many dogs ARE adopted after being abandoned or losing their families, an animal and a human sharing those circumstantial or superficial experiences does not make the human less human) and breeders trying to differentiate themselves from animal mills (like puppy mills).
But to me it's just a sale. A breeder is a breeder. And you don't "adopt" from a breeder, you "adopt" an animal that lost its family somehow. You buy from a breeder. Much better to think of yourself as an ethical breeder and put the standards you hold yourself to in that regard out for public display. Most people shopping for an animal aren't shopping for a rescue anyhow - they'd be going to a rescue for that.
And I will say this, rescues and adopt don't shop have done some serious work over the last few decades bringing our euthanized animal population down MASSIVELY. But I think it sends the wrong message if you're a breeder trying to use it. Making yourself look like a rescue case may get more sales, but it makes you look worse as a breeder, like you're just throwing animals together to make babies that need to be rescued rather than being proud of a product you've created and put time into and is worth paying for, even if that's just the care of selecting your brood stock from other breeders. To me, BUYING a bred rabbit is getting something someone put work and pride into while ADOPTING an abandoned animal is a charity case and done out of love. And both have a serious place, but they're very different.