Putting it into the three-color deck is advisable when the fourth and fifth colors of the theme are so undersupported that they need the help
Theres not really an alternative that does everything it does, either, making it very difficult to replace, especially in higher brackets
Theres not really a lot more to it the only real note is that if a currently conniving creature is killed, bounced, exiled, or removed from the battlefield in any other way in response to the connive trigger, you still get to draw the card (or cards) and discard a card (or cards), but youll have a tricky time putting the +1/+1 counter on a creature that is no longer there
Getting to use those cards as removal and then cycle them for draw is pretty powerful
But the nature of TCGplayers (and therefore, MTG Stocks) pricing algorithm was creating the artificially inflated price