If you want an argument against Batfleck*, ‘Runner, Runner’ is it.

Mister Affleck is cast as a ruthless criminal mastermind, and he mugs and smirks so much that it’s difficult to take him seriously. That chin dimple reads heroic, and he never acts hard enough to overcome it.

Now I think it’s stupid to worry whether any actor is good enough to play something as relentlessly juvenile as Batman, but if I were to indulge the premise I would say that his self-adoring puckishness would have to be worked around somehow, at least if one judges by this film.

The rest of the movie is some sort of ungainly cross between a kid genius movie like ’21’ and third-rate Elmore Leonard.

Justin Timberlake is back in school after a Wall Street flameout, and he’s putting himself through school with a combination of bookmaking and online poker. When he begins to suspect he’s been cheated, he heads to Costa Rica to confront the kingpin and get his money back. Sensing either moxie or brain damage, the kingpin hires him.

None of that makes any sense, but it doesn’t really interfere with the silly pleasures of the movie. The lavish, sweaty-linen lifestyle of the gangsters is appealing eye candy, and Timberlake takes a few memorable beatings from the local gendarmerie. Everything steams along merrily, provided you never reconsider the premise.

Will our hero escape with his soul? Will he fall improbably in love with the one woman in Costa Rica he should steer clear of? Do the answers to these questions matter?

You will not be surprised much, but it’s workmanlike fluff that you probably won’t regret streaming from Netflix, where it will be waiting for you well before Christmas.

No reason not to wait.

*Batman played by Oscar Winner Ben Affleck. Loathed by fanboys who believe he has neither the darkness nor the absurd vocal grit to play their Dark Knight.