So, folks who responded are conflating BIOS with UEFI. It's a common mistake - but they are very different things that serve the same purpose.

BIOS is older technology. It usually wasn't risky unless the board was somehow faulty, but there was always some risk because you were directly reflashing the CMOS.

UEFI is the current technology. If your board is less than 10 years old, you almost definitely have UEFI and not BIOS. It's stored in NOR flash memory on the motherboard.

UEFI's nature and design make it much simpler and safer to update. UEFI can be updated automatically within Linux; BIOS requires the board manufacturer's utility to reprogram the CMOS.

I'm simplifying some of this. But this should help explain the conflicting responses of what gets updated under Linux.