Laser-guided pool cue is kind of useless
Back in the days before my dreams of being an international pool hustler were dashed by noted Quebecois pool shark Fat Froggy Francois in a subterranean pool hall that smelled predominantly of monkeys, I practiced my skills on the original Virtual Pool. It was actually an excellent little program: the ability to project a laser-like beam from your virtual cue's tip and visualize the angles of a table, the way the cue ball would cause a cluster of balls to spread depending on slight degree variations of the shot... it was all was formative to my current impressive state of savant billiard mediocrity.
This Laser-Guided Pool Cue almost looks like a real-world equivalent of Virtual Pool's visualization mode... except as near as I can tell, the only thing it does is pulse a carbuncle-like laser tilak in the middle of the cue ball. That seems... not so useful, especially for $80.
The Laser-Guided Pool Cute [Hammacher]

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Especially useless, as it's seemingly impossible to chalk.
now if the ball was refractive it might actually sort of work... though I highly doubt it.
In no particular order:
i) the link is borked.
ii) the tip can be chalked: the laser is recessed in the middle of it, although it presumably reduces the amount of spin you can get on the ball.
iii) what it's good for is showing you how messed up your cue action is, which may, or may not, be worth 80$.
@3 link is borked but here's another:
http://www.hammacher.com/publish/72641.asp?cm_ven=CJ&cm_pla=1492714&cm_ite=Guaranteed+for+Life+at+Hammacher+Schlemmer&cm_cat=1414665
And then, in next month's catalog, they start selling transparent cueballs?
It might be useful if you needed to kill a zombie by jamming a pool cue through its eye.
You'de still have to move it around a bit to mash the cranial organ inside though.
The laser will get dirty.
Well, obviously you haven't figured out the secret ingredient, John.
It's smoke. Billowing clouds of thick bluish smoke preventing you from seeing further than the length of a pool table. Fine cuban tobacco smoke trickling up the side of your face and stinging your eye as you lean over the baize in your electric-blue pin-striped zoot suit. Thick puffs of acrid grey smoke filtering through the louvered closet doors where the piano player is adjusting his head.
It'll be just like you remember!
--Charlie
I would use the laser to screw with my opponent when it is his shot.
Worthless? It's pool... WITH FRIGGIN' LASERS!!!