Here is the critical reality of PS2 emulation: Unlike cartridge-based consoles, the PS2 requires a copyrighted firmware to boot. The emulator provides the hardware skeleton (CPU, GPU, RAM), but the BIOS provides the instructions for how to use that skeleton.
PCSX2 maintains a database of known "good" BIOS hashes (MD5, SHA-1). The official hash for a clean dump of SCPH-70012 BIOS v1.20 is typically: c1ffb2242e7336c009fae0a2e403ceba (varies by exact dump version). If your 200.bin has a different hash, it is either corrupted, a patched BIOS (with region mods), or a dump from a different revision. scph-70012-bios-v12-usa-200.bin
Hardware fails. Discs rot. The SCPH-70012 uses a laser lens prone to burning out after 1,500 hours. Without BIOS dumps and emulation, the library of PS2 games (the largest of any console) would eventually become unplayable. BIOS files are historical documents—source code for a cultural artifact. Here is the critical reality of PS2 emulation: