Because the Xbox "Coppermine" CPU has the same L2 cache size as a "Coppermine" Celeron (the main differentiator between Pentium and Celeron at the time), the Xbox CPU is sometimes called a Celeron instead of a Pentium III. The Xbox chip retains 8 way cache associativity of a "Coppermine" Pentium III instead of the 4 way that Celeron has, so it's not quite what you'd get with a PC Celeron chip. Ultimately this configuration is only used in the Xbox, so if Intel and Microsoft want to call it a Pentium III I guess that's what it is.
