ΔE 26.2, loose: different enough that you should pick on purpose. Kakophoni Purple is noticeably darker, much more saturated, warmer than Blue Violet.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Kakophoni Purple is noticeably darker, much more saturated, warmer than Blue Violet.
The same difference applies the other way round: Blue Violet is noticeably lighter, much more muted, cooler.
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 Blue Violet on the colour wheel See Kakophoni Purple on the colour wheel
All matches: Blue Violet equivalents · Kakophoni Purple equivalents