If that information delivered to the PC is incorrect, it could result in application instability or data loss.
Every computer has inside it a real-time clock.
The BIOS software interprets the first two digits of the year. It would, for example, add the 19 to the real-time clock's 99 to derive a 1999 date. Problem is, not all BIOSes are programmed to know that the date change between 99 and 00 means 2000 and not 1900. There's good news, however. Most BIOS software sold in the past few years is programmed to interpret the date change correctly.