The cursed gold is in your deck regardless.
That much is true, but that doesn't mean that buying the Hireling is going to be a great option. If you ignore the CG that turn and use your coins to buy Silver, you can use that towards buying the Hireling on the next shuffle, which will be of similar overall utility to doing it the other way around, but won't cost you a point. And that's assuming that Silver/Hireling is the best you can do on the board, in which case heaven help you.
Case 0: There's no decent trasher. Hireling/Silver/Curse seems good to me. Without trashing, it going to be a long time before you are reliably cycling through your whole deck, and hireling draws at least 2 cards per shuffle, giving value well in excess of the lost value due to the curse. You want it ASAP, because silver/silver isn't going to get you to 6$ before you can get value out of the Hireling
Case 1: There's a reasonable trasher (sifter?) at 3$ or less.
Case 1a: the trasher is terminal. I can see being underwhelmed by hireling/trasher.
Case 1b: the trasher is non-terminal. hireling/trasher/curse seems way stronger than silver/trasher. Because neither silver/silver, nor silver/trasher are going to get you to 6$ very fast if you are intent on treating cursed gold as dead.
Case 2: There's a trasher at 4-6$.
Case 2a: if the trasher is strong, trasher/silver/curse is probably better than hireling/silver/curse
Case 2b: if the trasher is slow but reasonable, trasher/silver/curse feels bad, but hireling/silver/curse will probably be worse. Even silver/silver beats those.
So basically, hireling is going to be satisfying if there is no good trasher at all, or if there is a good cheap non-terminal trasher like forager.
There might be as many as 10 cards that make the hireling good, and maybe 16 good trashers that are better than hireling, and maybe a handful of other non-trashers that make up for adding a curse to your deck.
The default case 0 is that hireling is good and reasonable!
How many exceptions are there?
maybe there are 20 trashers that support the trasher/silver and trasher/silver/curse openings...
maybe there are 15 (spitball!) non-trashing 4+$ cards that are worth the curse MORE than hireling is.
How often is one of those 35 cards, out of about 300, in a kingdom where only 8 kingdom cards are up for grabs after pooka/hireling?
odds of none of the 35: (265/300 * 264/299 * 263/298 .... ) = 36.6%
So more than a third of the time that hireling/pooka are together, hireling will be strongly viable on a 6/3 split.
Alright, what did I fuck up?