It is key for desktop motherboards, at least AMD ones where they reuse the same socket over multiple CPU generations.

I bought a motherboard and a new AMD Zen 3 CPU together recently. The motherboard wouldn't POST because the BIOS was too old to and didn't have Zen 3 support.

The only way to get it to work was to flash a new BIOS using the out-of-band update tool that works with just the PSU and USB stick attached.

Without that you would need a spare CPU knocking about...