Everything can be improved upon, engineered from paltry to perfection
As a result, they're a little controversial, since many lend themselves to less focused strategies and decks, where you just want to cram in all the best cards in your collection
If you sacrifice Lucius as the cost for Bone Splinters, its trigger happens while your spell is on the stack
Sure, your opponent gets too as well, but if youre dropping a creature with an exceptionally powerful enter the battlefield trigger, like Atraxa, Grand Unifier, a creature that is practically unstoppable like Emrakul, the Aeons Torn, or an enchantment that gives you free rein to do whatever you like Omniscience, you basically guaranteed a win
I think I am prejudiced against Exert, Cohort, and all tapping mechanics