You should read the history of KG2, which was one of the backbones of the LW bomber units in the West 40-44. It was almost exclusively equipped with Do 217s, and did use them only in a level bombing role. They keept attacking Britain even outside such well-known offensives like the Baedeker or Steinbock raids, even in single-plane daylight raids in 42/43.
Overall, it was far from being "infrequent" that the 217 carried out conventional bombing roles.
For example, in June 1943, 4 out of the 10 bomber Gruppen the "Angriffsführer England" had at his disposal were equipped with Do 217s.
It's no "footnote" and can fill a very important role in game - a more survivable mid/late war German bomber.