While psi_lifeup has an excellent write up from when the card launched, time has moved on. Multithreader has a new sibling from Ashes, Rezeki. I think that people are reaching for the shiny green thing where this might work?
Rezeki is clean. 1 and for outside shaper though, it's the same influence as multithreader. And I suppose that you can have the credit carry over to the next turn. But when are you not breaking ice or playing cards?
Multithreader is more restricted, it costs more if you don't run straight after install. You also need to run each turn to activate it. It sure is a shame that the name of the game doesn't mention running... The payoff is an extra who knows if that makes better in general. But if you're running each turn, a free credit is stil a credit.
The real downside is that it costs influence in shaper.