If the corp used this, gave me 3 dollars, and then I facecheck into trollbooth, how is that a gain for the corp. The runner lost 1 click, you lost 3 (5 from the card 3 of your own) in order to rez something. Now, my economy isn't hurting any more, and I know what breaker I need. If you needed this card to rez Trollbooth, you are most likely broke again.
Giving 3 credits to a runner enables lots of things. Assuming best case scenario, they are at 0 dollars. They can now credit, credit, gamble, run/inside job/siphon etc... Before it would be an entire turn later. 3 credits lets them use Lucky Find (Not that I think that card is worthwhile). They can easy mark, gamble, install breaker, run through something. They can install desperado and start running. They can take 1 and sneakdoor twice.
Giving money to the opponent is generally a bad thing. I can't see where gaining 5 credits is ever worth using a click, a card, and giving the opponent free money (Outside of closed accounts shenanigans. Surely you have a solid deck now, what would you replace to add this? Another econ card? Ice? Even if it gave a net gain of 7 credits (Cost 3, gives 7) I would be hard pressed to give the runner just to put me in restructure mode. I would rather at that point, cred, cred, hedge and get to 9 without giving my opponent free psuedo accesses.