Yes, he is. Except in the matter of mowing. Camomile doesn't need it, because it takes for ever to establish itself and spread into a sward. Meanwhile, the patch needs to be hand-weeded, which is far more labour- intensive than mowing. Camomile is expensive, given the number of plants you need to make anything resembling a lawn; even when they do start to join hands, they are not robust enough to be walked on often.
However, the plant does well on light, sandy soil, where grass might struggle. It is also resistant to drought. If Mrs Southwell wants to experiment with a small patch, she should look for the non-flowering cultivar called `Treneague'. Plants should be set four inches apart.