Figgy Pink vs Decadent Purple

How close are they?

ΔE 18.0, loose: different enough that you should pick on purpose. Decadent Purple is more muted, cooler than Figgy Pink.

Can I use Decadent Purple instead of Figgy Pink?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Decadent Purple is more muted, cooler than Figgy Pink.

Can I use Figgy Pink instead of Decadent Purple?

The same difference applies the other way round: Figgy Pink is more saturated, warmer.

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.