Plays like this often result in massive damage swings, sometimes ending the game
Where the card shines, though, is in its overload ability, which lets you cast the card for a higher cost and extends its effect from a single creature to each one you don't control
Some of the attacking creatures will probably be blocked and killed, but you can either let them die, or sacrifice the blocked ones and start benefiting from their abilities
Once per turn (Quick Effect): You can declare 1 Attribute
Parting Thoughts isnt efficient at any one thing you want to do, but it has enough options to be worth a deck slot
A single Threaten ETB effect can help turn the tide of a limited game, but it's situational and falls flat in multiplayer Commander games