You'd think someone would have dug up a citation for this, but Wikipedia says (for the PS2):
>Some incorrectly speculate it was used as an attempt to help classify the PS2 as a computer to achieve tax exempt status from certain EU taxes that apply to game consoles and not computers (It was the Yabasic included with EU units that was intended to do that).[citation needed]
and Linux on the PS3 was used as a marketing point.
>Some incorrectly speculate it was used as an attempt to help classify the PS2 as a computer to achieve tax exempt status from certain EU taxes that apply to game consoles and not computers (It was the Yabasic included with EU units that was intended to do that).[citation needed]
and Linux on the PS3 was used as a marketing point.
https://en.wikipedia.org/wiki/OtherOS - both these pages are really bad :/