I slept on this card for too long. 4 resources just seemed like a lot to pay for a cancel, when most other cancel events cost 0-1, but when I thought more about it, I realized it's a pretty good rate.
Sure, this costs 3 more than Ward of Protection, but you get to draw a card and avoid a horror. Considering that rogues tend to fear treacheries in general and horror in particular, isn't that a good deal? (If you imagine that the card drawn is Emergency Cache, then the total cost to use this is 1 resource +1 action) Most cancels actually do have a significant other cost, or limitation, whether it's dropping clues, fishing for tokens, or being very delayed.
I don't think of this as a "big money" card, a phrase I now associate with hoarding. You probably don't want to spend 4 on this if you're trying to turn on The Black Fan or if that could be spent to crush two more tests with Well Connected. Instead, this is a classic "medium money" card.
Since this card's release, rogues seem to get richer every set. They've got tons of ways to generate resources passively while they are playing to win. This means that once they've set up, they're likely to accumulate a stash of 6-8 extra resources by the mid-late game kind of by accident. This isn't necessarily enough to make buying all the big money payoffs a priority, or you might just have other plans for your XP. But it makes running some Counterespionage totally reasonable.