This photo does make the point!
The flower is the rare “Austral cornflower” Stemmacantha australe (also sometimes called the “native thistle, for obvious reasons - though it’s an inoffensive, non-prickly plant. Like the weedy introduced thistles, it is in the daisy family (Asteraceae).
The larger butterfly is the rather curiously named “pink grass-yellow” (Eurema herla), and this old lady has obviously seen better days.
She’s being rather pointedly ignored by an equally elderly pea-blue - possibly the long-tailed one (Lampides boeticus).
They may not have laid their eggs in my garden, but if they have, the yellow butterfly would have chosen a Senna, while the blue would have chosen something in the pea family - perhaps the Crotalarias which attract so many little blue butterflies to our garden.
Use the search box at top left for another posting on the Stemmacantha, or search for Asteraceae, the daisy family, for some other butterfly-attracting daisies. The search box will also find more information on a local Crotalaria, or on local Senna species.
All three kinds of plants are very good for attracting butterflies to our local gardens