First, is this card worth using if you don't get the full 8 discount? Maybe - especially if you have ways of avoiding the tag (a la Forger, On the Lam, and even the spoiled No One Home). But those cards all cost clicks to install already so the per-click savings you're getting have to be at least 3 per so that you're matching the full discount you get from just clicking to remove the tag regularly (save 8 , spend 2 on the tag removal for a net 6 over 2). Therefore, using Forger as the easiest example, you want a discount of at least 7 - perfect for those eyeing the spoiled Amina! :D
So let's get into what's really worth using this card on - the full list is available down below but I'll sum up which cards are must-look-at's (Sorry Security Nexus, Monolith, Mass-Driver, Morning Star):
Femme Fatale and Rachel Beckman. Yup, that's it. And the latter card insta-kills itself if you don't avoid the Credit Kiting tag. Still, surprise Femme to snipe a single gear-check remote is a nice "gotcha" moment when the corp thinks they have a scoring window. You could even Credit Kiting a Femme for a Stimhack
run after getting your account closed.
All in all though, this card currently lacks the required support in-faction until a viable blue tag-me archetype appears or more expensive blue cards are released. Personally I'm of the opinion right now that the play condition isn't a problem - in fact, Criminals want to be making early-game central server runs anyways! If you're looking for per-click economy of at least 3 per , keep it simple stupid!
Full list of installable runner cards at 7 or more: EDIT: See Krams' comment above.