Not necessarily! Just because there's no monetary prize doesn't mean that you're not getting anything out of it. A lot of widely successful games like Hollow Knight, Celeste, Baba is You, and Night in the Woods started from game jams like Ludum Dare and Game Off! There's a whole community that would be willing to give your game some good feedback and suggestions. And who knows? A good prototype would make for a good pitch to a publisher, which would then make you some money!
I hope you change your mind!