along came a spider

I had fun creating this week's illustration for the Blotter, but I also thought it raised an interesting question.
The item in the CL crime report had to do with a man nicknamed "Spider-Man" who was accused of beating his wheelchair-bound girlfriend and stealing her pain medicine. Given the grim subject matter, I didn't think my usual playful comic style of drawing was appropriate. What emerged was the more sinister-looking style you see above.

My question is: Do you think it's bad for an illustrator to play around with multiple styles of art like this? Or is it better to just choose one thing and always do that? (I'm thinking here of artists like Luc Latullipe or Steve Mac, folks who have settled on their one signature style and seem to do only that. I really love their work.)

The week before my drawing was far more playful, a carefree doodle about a man caught shoplifting sausages. Fun times!