You're probably right. Can't speak for
Oz or NZ, but merger names are widely used here in South
Africa, probably less so than before, with globalisation providing more choices. But back in the day, when Afrikaans-speaking families in particular used to follow very rigid naming rules (first son named after paternal grandfather, second son after maternal gf, daughters pretty much the same, and so on) there was a risk of several cousins having identical names, and of course people coped, but some of them chose not to and went the merger route.
A friend's younger sister,
Jeanine (not a typo), married a
Rudolf and they named their first daughter Runine. Which makes Emmalise look positively ordinary!