It seems like an amazing trick to play in mono white. Does it see play? Nobody is expecting a counter against soul sisters, but you can surprise them with this.
{Mana Tithe}
No, mono white doesn't use it. Mono white is hardly a deck that sees plays. Usually black and white are in play.
The cards sucks though when there are better cards than it. Surprising your opponent with the card won't affect them since 1 mana is not the end of the world most times. If people let a card get countered by it, it would be too early and no really effect them if they actually know how to play, they would play around it.
Some versions of Hatebears run it.
It can be a really annoying trick sometimes, but so often it seems they can just pay the 1
You have to time it right and make sure they're tapped out.
I've used it as a one-shot troll card. My opponent would tap out, I'd cast {Mana Tithe}, then SB it out next game and have them always hold back mana and play around it even though it wasn't in the deck anymore. It's.... Ok. Usually, they can just pay the mana, but it's for to just say "No" to a huge {Sphinx's Revelation} or {Entreat the Angels}
{soul tithe} seems to be a good way to get your enemies goat when they think they've brought out the heavy artillery XD
This seems like it would be useful if it was standard legal, which it isn't. In a modern deck, I feel it might slow down the process of winning too greatly to be worth playing.