ΔE 12.5, fair: the same colour family, but not a straight swap. Warlord Purple is noticeably lighter, more saturated than Cobalt Violet Hue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Warlord Purple is noticeably lighter, more saturated than Cobalt Violet Hue.
The same difference applies the other way round: Cobalt Violet Hue is noticeably darker, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Cobalt Violet Hue on the colour wheel See Warlord Purple on the colour wheel
All matches: Cobalt Violet Hue equivalents · Warlord Purple equivalents