The problem with double-precision in video games is that the GPU hardware does not support it. So you are plagued with tedious conversions and tricks like "global vs. local coordinates" etc.
100! OTOH
- Constant factor scaling between game and render world space fixes a lot (gfx often need less precision than physics).
- most view coords are in view or clip space, which are less impacted, so large world coords tend not to code-sprawl even when introduced.
