Minnesota implemented a similar law in 2019 and it's really made no difference. You see idiots on their phones all the time not paying attention.
Laws like this will always be toothless if they rely on you to be physically stopped by an officer and if it's a fixed fee penalty.
We know who is far more likely to be stopped by police and a fixed fine system penalizes the poorest the most. If cameras were used and fines were assessed based on percentage of income OR it was a points system that could lead to revocation of license I think they'd be more effective.