Six mana can be a lot, but red has no shortage of rituals or Treasure tokens to get this out early, and while you cant cascade from copies of spells, you can discover if you cast cards like Trumpeting Carnosaur or Hit the Mother Lode, which then gives you more copies
The best deck I have used it in by a country mile was an Aluren based combo deck where you were using the card as a way to dig for the combo pieces you need
Double Trigger Normal Spell (1) Activate 1 of these effects (but you can only use each effect of this cards name once per turn)
Who needs creatures when you can win with cards like Shark Typhoon, The Wandering Emperor, and Teferi, Hero of Dominaria
That being said, if I wanted to be scientific and care about probability, I wouldnt be playing a coin flip deck in the first place
Turn their landbase against them and do a significantly larger amount of damage than your standard issue Lightning Bolt or Shock