Attributing it's hit status to the perfect intervals is ignoring all of the other choices (and supporting infrastructure) that go into making a hit. It's like saying that the Dodge Charger was a successful car because the windshield wipers are of a certain make.
Side note: It may very well be a sampled trumpet.
“"Safe and Sound's" trumpet line is partly responsible for the popularity Capital Cities is currently enjoying”
>>>The trumpet line in ‘Safe and Sound’, for example, didn’t appear in the production until nine versions into the song. The final version, on a whim, we decided to try using a trumpet, a live trumpet, to play that line and it stuck. We ended up actually using the trumpet a lot throughout the album after we included it in ‘Safe and Sound’.
"It was trial and error, right? We felt like that line was an epic line and we thought about different instruments that sounded epic, and the trumpet is obviously one of them,<<<
The thing about trumpets is this: Their fifth is a little “sharp” because it’s a perfect just intonated fifth (i.e. a perfect 3/2 ratio).