I love the fac they've finally incorporated this. It seemed like such a peasely feature to have, but it really makes a gameplay difference, esp. with how trainers "find" you.
Also, if a bush shakes, you won't risk getting involved in a different wild battle if you're diagonally beside it, since you could just dash into the shakey bush without having to pass by one in an L pattern.
If "X" is you and "*" is a shakey bush, you would normally need to go ->v or v-> to get to the bush. Assuming the feature comes back, you could just dash horizontally into it without risking anything.