If you aren't setting up for an immediate win, you can run Revel in Riches as a poor man's Black Market, but not only is that an inefficient use of the card, you'll immediately become archenemy of the table, so this is not advised
that is, its ability to remain interesting even after being played several times
Combine shrink effects with the occasional card draw and you'd think this assassin would be better known on the battlefield
Im not above playing a Dark Ritual in my Vintage Cube decks for value with the expectation that sometimes Ill just need to go fast, and Treasure Vault can serve as a similar mana boost for any color of deck in a pinch that otherwise is just an untapped land
Also, the land comes in untapped if you have one land or less in play which makes it decent in the early game
The delve isnt just for making it cheaper either though, as itll enter with a +1/+1 counter on it for every instant and sorcery you exile to pay for the delve part of the cost