On my initial reading, I was getting ready to dismiss it towards a budget Mindslaver in a steal cards archetype
See the full decklist for Deep Clue Sea
Wizards don't like to reprint a mechanic without having more of it in a set
The decks are already going to be packed full of instants and sorceries for these commanders to take advantage of, and with Font of Magic on board, a one, two, or even three or more mana discount on those spells could lead to some wild turns
Note that, like Snap, theres a bit of an asterisk here where in the right deck it can be much higher on the listif youre very good at spending colorless mana, then I think this moves up to around #6
Each color traditionally gets access to specific types of cards and strategies, and powerful cards typically cost more mana than weaker cards