I am not sure that it matters, functionally. Also the players aren't going to be required to use them (one will be available for visiting team too).
The thing is, they were really cool during a time when a baseball game wasn't as saturated in non-game entertainment. Now it will just be another thing going on amidst mascots, hot dog launchers, races, promotions, etc. Maybe it will increase pace of play? (But I doubt it.)