It contains libraries for early Japanese-specific software that may not be present in later Western releases.
For modern users, SCPH10000.bin is most commonly used with the emulator. PCSX2 requires a legitimate BIOS dump to function because the BIOS contains copyrighted code that cannot be legally distributed with the emulator itself.
The SCPH-10000 was the launch model exclusive to the Japanese market. Unlike later versions, this specific unit lacked a built-in "Expansion Bay" for a hard drive, instead featuring a PCMCIA slot on the rear. Because it was the first iteration of the hardware, its BIOS is unique, containing early versions of the PS2's system software, the DVD player (which initially had to be loaded via a separate "Utility Disc"), and the iconic "Towers" startup sequence. Technical Anatomy of SCPH10000.bin
Without the BIOS, the PlayStation 2 hardware is essentially a box of inert silicon.
Whether you dump it legally from a 24-year-old Japanese console or stumble upon it in a forgotten corner of the internet, remember its significance. It is the ghost in the machine—the first breath of the most successful console ever made.
Projects like and PCSX2's "Full BIOS" replacement attempts still look to the 10000 dump as the Rosetta Stone for understanding how the Emotion Engine truly boots.