They cleaned Trivago guy up for a few of their commercials (grown-up man dress shirt with jeans, he was shaven), but he’s back to t-shirt 'n whisker-stubbled “creepy uncle who lives in a van by the river” mode. I can’t put my finger on it, but he also seems even creepier than before . . .
You might enjoy this YouTube video in which the actor who plays the “Trivago guy” explains his stubble (at the time, he had a job playing a scruffy, unshaven rock star on a German TV show). He also reads some tweets complaining about his appearance, and notes that a couple of other countries have their own Trivago guys who are similarly groomed.
He’s supposed to be sexy. If you pay attention, every single leading man or just guy who’s supposed to be sexy has the magical perma-stubble/shadow. Not just some of the time, in scenes where it makes sense that the character hasnt shaved in a while, but always.
AIUI, Trivago actually is a German company, and hired him at first to do the German ads. (He knew no German before taking the rock star role; he obviously had the gumption, and the magnetism, to put himself over.)