This is a very traditional Danish bread. In the 1600's a lot of half and partial penance and holy-days where combined into one day of prayer. "Bededag" (day of prayer). But the baker had that day of too, so he prepared some bread that could be easily roasted. Hveder (Wheats). It is a recipe from mid 1800. So all Danes knows this tradition and eats Hveder on Bededag. The fourth Friday after Easter.
The religious aspect does not play that big a role anymore for this tradition, but the bread has become its own tradition, and we still make and eat them on Bededag.
We also eat a very similar bun the rest of the year, but then it is called a "krydderbolle" (spice bun).
I also use this recipe for burgers and sandwiches. Which it is very suitable for.