There are some decks that rely entirely on Threaten effects to function, such as certain builds of Hofri Ghostforge, The Beast, Deathless Prince, or Obeka, Brute Chronologist, but stealing things shouldnt be limited to just themed builds
The few planeswalkers you are allowed to use as your commander are sufficiently narrow and fair that they do not have the same oppressive effect
When dealing with things that have tempo or rhythm, humans are more comfortable with odd numbers
Collectors want assurance that their cards meet high-quality standards
Grind is a nice way to put out -1/-1 counters, and the aftermath of Dust makes a huge impact if you spread around three or more negative counters
The weighting and effectiveness of Go for the Throat is just spot on