Maybe it’s just some “sweet spot” for certain usual bpm/lpb values. Don’t forget that most modulation and automation data is interpolated at tick rate. Tick rate too slow, and you’ll hear a “steppieness” in some automations. Tick rate too fast, and it’ll use significantly more cpu power in some setups. Triplets in a single line by delay commands make little sense to me, other than if you’d use very low bpm/lpb values. Single line triplets would be way to fast to make sense in “normal” setups - to ease triplets, people would rather use 6 or 12 lpb than 12 tpl. Ok, the faction of making music with very low linespeeds - very compressed patterns rather than lines flying through faster than you could read them - I guess you’ll have to up the tickspeed then to compensate for steppy automations in some cases?
But maybe there are some subtle advantages in “groove shifting” notes in between a line when using tpl values multiple of 3 - same goes maybe for the “feel” of automation data being interpolated at such intervals. Like it’ll sound more funkey then, or whatever, who knows.