If you're proposing a law, and a study says that 12% of people would violate this law, it's a major indication that this is a bad law.
Studies seem to indicate that around that many people admitted to or have drove drunk in America for example. Does that mean drinking and driving laws are bad?
There's an argument to be made that texting while walking can be dangerous because if you're sharing a small space with cyclists or others then you're potentially leaving yourself open to colliding with them. And ultimately the cost to fix this problem is low and unobtrusive (ie just step aside).