BC is a huge seller for me. I only have so much room for consoles. Not only does the hardware take up space, but that is an HDMI input and a power input. Add in extra controllers... yeah, being BC is a massive get, especially if the controllers are BC.
Essentially being able to use my ps4 controller and upgraded HDD, makes the ps5 $160 cheaper... does that matter? Absolutely.
And for the sake of argument, perhaps I can sell my ps4 for $150... add that to the $160 savings, and now I am saving $310. In my book, that is a massive selling point.