All phones with Mediatek processors have this pre-installed logging application and the data it collects is massive,right up to the plugging/out of the phone from the charger.
What is this service targeted towards? One could say for troubleshooting and modding purposes but Mediatek generally targets the lower end (limited-capabilites but affordable) market. Besides,I don't think I've heard of any other chip maker that ships out built-in data loggers.
EDIT:My question does not pertain to what this service does(which has been covered in other questions) but to the reason for the existence of such a program.I understand that it's difficult to answer this question so even headers would do the job.