ΔE 15.4, loose: different enough that you should pick on purpose. Alizarin Crimson Hue is noticeably darker than Poppy Red. They are different kinds of paint: Army Painter Poppy Red is a one-coat contrast-style paint and Golden Alizarin Crimson Hue is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Alizarin Crimson Hue is noticeably darker than Poppy Red. They are different kinds of paint.
The same difference applies the other way round: Poppy Red is noticeably lighter.
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 Poppy Red on the colour wheel See Alizarin Crimson Hue on the colour wheel
All matches: Poppy Red equivalents · Alizarin Crimson Hue equivalents