It’s certainly not something to base a business plan around…. unless you’re a lawyer who also specializes in being a patent troll.
IANAL, but as I’ve read the stuff around copyright, if higher damages can be proven due to the infringement (say, destroys millions in box office revenues), then that’s the liability. The registration bonus simply says that you can assume up to $150k/infringement without proving it. Of course, you’d have to convince a court/jury that it’s reasonable amount, and anybody big will have plenty of lawyers available to defend it. So, the normal caveats, of the, can you afford to successfully prosecute a case to a court, apply.
While I’ve not actually registered because I haven’t reached the self-publication point (I am contemplating it), I’d imagine there’s some nice mental benefit of getting the library of congress to acknowledge your works too. And, IIRC, the cost is pretty low ~$30 or so last time I checked.