In my time, of attending primary school in Gouda, the Netherlands, learning to read was still based on the strong reliance on phonics. All the vowel sounds were taught, by rote, using these illustrations.
(AAp, nOOt, mIEs, wIm, zUs, = monkey, nut, girl’s name, boy’s name, sis……)
In the 1980s or so, nostalgia produced lots of items, like these. (A little like having Ken Done art on things.)
Many of us arrived in the so-called ‘wave’, of immigrants from the Netherlands in the 50s and 60s and still know these illustrations.