Naturally, if another artifact with or without a subtype somehow gains the Vehicle subtype, it wont gain any of these specialties just like that
Youre more likely to see a value hold on, say, Eternal Witness (which can port into most green decks) than a high-powered green commander (which can only really be used as the commander in one specific deck)
For fun, discovery, and the social experience of cracking packs together, boosters justify their premium
Guide of Souls also serves as huge energy ramp in an aggro deck
Tossing around two +1/+1 counters on all your creatures while also dishing out some combination of lifelink and double strike to one or more creatures is gnarly, and you can split it up into two instances of the effect as well
Finally, Chance for Glory