I'm a fan of this card. It's a lot more effective than you'd think. When I've used it it's been alongside movement effects and other economy denial style cards. Mustang, Walk the Path, Shadow Walk and the 108 Righteous Bandits' movement tricks all allow you to steal some ghost rock and then move somewhere safe. Taking someone's ghost rock can seriously disrupt their plans and the boost can accelerate your own. Combine it with Tummy Twister and Deliberate Infection to increase the upkeep of their dudes, and deny them as much production as possible, and you'll soon stall your opponent's deck. It's on value with the California Tax Office which is at its most powerful in such a deck.
While not something I've got round to, using it in a Sloane deck to build up bounties and set up situations for an Experienced Allie Hensman to exploit would be another way to use it. It can combo with The Place - if you're lucky it could net you four ghost rock and four bounty in one use, which Desolation Row would love. If you're trying to make Plasma Drill work, then using this to remove your opponent's ghost rock reserves before you drill sounds like a good idea. Running this and Confession to remove your bounty gets you even more ghost rock from it, and if you don't want stacks of bounty making your dude a juicy target you can always discard The Evidence.