It's playable in major Eternal formats, namely Commander, Legacy, and Pauper
By contrast you essentially never cast Boon of the Wish-Giver
A Dion, Bahamut's Dominant Commander deck is a Knight Typal deck, meaning it's a deck that focuses primarily on one creature type, in this case, Knights
Omnaths color pie is highly versatile, which opens up lots of doors for deckbuilding, but I prefer to focus on ramp and control in this case
Trample, haste, annihilator 1 (Whenever this creature attacks, defending player sacrifices a permanent of their choice.) Illustrated by Helge C
Then the Hero is a nice four drop 3/4 that has two attack triggers