The Son and Knock at the Cabin seem to agree with one of my core artistic tenets:

If a Broadway belter appears in your non-musical movie, then you damn-well better find an excuse to insert a song-and-dance scene that demonstrates their triple-threatery.

I mean, so few actors boast musical chops, why waste the opportunity to let them flaunt their skills in front of a global audience — what did Ulla say about flaunting it if you got it?— especially because it’s easy enough to dramaturgically justify this flaunting. 

Cases in point:

No reasonable viewer would expect The Son and Knock at the Cabin to clear out for some boogie; as such, to those familiar with the stage careers of Hugh Jackman and Jonathan Groff, these sequences incite the sort of surprised glee that children enjoy when they discover Easter eggs. If you’ve been riding with Wolverine since before he was Wolverine (helloooooooOklahoma!), or if you saw Groffsauce first get Totally Fucked, these brief moments of crooning and gyration feel like subtle nods to the wider range of their performance capabilities. 

Here we all are, insidiously preaching the gospel of musical propaganda, one non-musical movie at a time.