ΔE 18.8, loose: different enough that you should pick on purpose. Blueberry is noticeably lighter, more muted than Violet.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Blueberry is noticeably lighter, more muted than Violet.
The same difference applies the other way round: Violet is noticeably darker, more saturated.
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 Violet on the colour wheel See Blueberry on the colour wheel
All matches: Violet equivalents · Blueberry equivalents