There's no advantage to building over the deck size minimum strategically in magic (there are in some other games) that offsets the downside to consistency of even one extra card
Flashback Flashback is another very common example of alternative costs, but there's a hoop you have to jump through: The instant or sorcery has to be in your graveyard (rather than in your hand) for you to be able to flashback it
However, the ability to evoke when you need to is very powerful as you can answer creatures like Ragavan, Nimble Pilferer, Murktide Regent or a creature carrying a Colossal Hammer, and the decks that play Solitude tend to be able to recoup this card disadvantage pretty easily
That is the reason, custom card games may feature unique dimensions for differentiation
The artwork was illustrated by Masakazu Fukuda
Its becoming a daily tradition