The other possibility is playing Invasion of Regatha in a dedicated burn deck since the backside seems pretty powerful with Play with Fire, Lightning Strike, and friends as a weird twist on Torbran, Thane of Red Fell, although I'm not sure a burn deck wants to use multiple burn spells or attacks to remove the five defense counters to defeat the battle
Meren decks grind opponents into submission through relentless value
Festival of Embers Does Standard want an Underworld Breach variant at five mana
Being unable to block makes it a card you only really want in aggressive creature decks but his light coloured mana requirements, artifact/discard synergies, and other many perks make him pretty common to see
So you have a weird situation where you already have an established board (past turn-four) and you try to push further with this, or you somehow try to bank on its haste effect using freshly-transformed permanents
Halfling has a ton of potential with the plethora of Legendary spells in Magic and could definitely become a multi-format staple
