For more on this topic, its nuances, and why it’s hard to give rules of thumb when so much is case-specific, see also:
That tip mentions this deeper dive, which includes a lot about subtasks with examples and context:
Bonus subtasks-related tip: So many people are still blown away to learn of this completely hidden Asana feature:
As Bastien noted, I’m often a subtasks proponent, but it really depends. During my Asana AMA for Nonprofits earlier this week, I offered a participant an alternative to eliminate subtasks in favor of a custom field; it’s an art to choosing and combining Asana features for workflow success.
Has a winner been declared in Marquis vs. Bastien? I say they’re both winners, as are all readers who benefit here.