First and foremost, this is a date and dates should be fun. Conveniently, bowling is fun, even if you suck at it. Because, guess what, there’s beer. And beer is fun. Personally, if my date didn’t want to drink a beer while bowling that would probably be a huge strike against him. Pun intended, obviously.
But back to learning if your date is a monster or not. Bowling is a window to the soul. Okay, that’s extreme. But it’s at least a window into how people handle competition. Seeing how someone reacts to winning and losing is hugely important. So if they beat you and then scream, “IN YOUR FACE!” and take a victory lap around the alley, you can assume that they will be a crazy sideline soccer dad/mom. If you win and they say, “This game is STUPID” and throw their shoes down the lane, maybe you don’t want to attend game nights or weddings with this person.
[Thankfully, when I turned out to be an extremely poor loser at bowling, my boyfriend still wanted to date me. But he also forced me to play Dungeons and Dragons because “it’s a team game” and you won’t “get as mad at me.” So view that as a cautionary tale and be a good sport, OK?]