Yeah. If you draw Golem+X, you play the Golem, and the Scheme will give you the +1 action to play the X. If you draw Golem+Scheme, you play scheme first, then Golem to draw/play the X. So you're only in trouble if you draw all *three* in hand at once.
The biggest hurdle in this strategy is the time to buy that Golem - you need to get the potion and then draw 4p before an alternative strategy has time to get set up and win. But I think getting a single Golem can be done in reasonable time - it's about as hard to get as a Gold, and the scheme and the X are presumably easy to get with it.
I think the biggest thing this clashes with is good trashing. If there's ways to play the X every turn or almost every turn without a Golem, then a potion detour is slow.
Seems like it's powerful enough that you should at least consider it whenever there's Golem and Scheme on a board. And as Dstu is showing, a strong attack seems to make it a rout.
I'm curious how Scheme+Golem+Smithy does against the optimised BM-smithy bot. You probably want to open smithy-silver or smithy-scheme, then pick up potion on the first reshuffle, golem on the second reshuffle? Opening potion and hoping to get a first-shuffle golem seems low-probability.