"If I have missed the point I would love someone to explain it to me"
The end goal of tagging and tracking sharks is not to allow surfers (and others) to monitor movements via an app. The purpose of the app is not to allow surfers (and others) to avoid a select few sharks! The fact the app was reported so widely in the mainstream media should give some idea of the widespread interest in the data.
Of course it is the potential interaction with humans that drives this interest, however in this case it is the relative lack of interaction that is noteworthy. Assuming the observed behaviour is representative then these sharks have been there in the shallows all along, mostly ignoring people/surfers.
The first stage of any species focused conservation effort is to fully understand behaviour, movement, habitat use etc. The first stage of any habitat scale conservation effort is to fully understand the ecology of that habitat. I suspect you will find plenty of published research in the scientific literature utilising data from this tracking study.
The app is a great way to allow public access of basic data, generate interest, raise the profile of the work, and ultimately raise funding to keep it going.
Releasing tracking data from dolphins and whales would likely lead to increased disturbance with no real positive outcome for the animals. There are enough places where you can view and even interact with these animals anyway.