The main benefits of CATCH from a health professional's point of view are:

Raise confidence in self-care
Parents and carers are more confident to provide self-care for their children
Supply familes with trusted health advice
A common approach to children's health is promoted, in that parents, grandparents, carers and health professionals are all being provided with the same, clinically-sound information which is up-to-date and approved by doctors in the local area
Reduce unnescessary hospital visits
Ultimately, pressure on local NHS services is reduced and unnecessary A&E attendances are reduced.
CATCH started as a project focused on the Cheshire East area. The concept of a health app was originally borne out the council's Annual Report of the Director of Public Health, 2013/14, which among many other findings, determined that large numbers of young children in Cheshire East are being taken to A&E and are being sent home with advice, as medical treatment wasn't required.

Of course, there could be many reasons with A&E attendance for children aged 0-4 in Cheshire East is far higher than the national average, but one explanation could be that some parents lack the confidence and knowledge to self-care when appropriate.

To remedy this, Public Health Cheshire East, NHS Eastern Cheshire Clinical Commissioning Group (CCG) and NHS South Cheshire CCG came together to jointly commission the CATCH app. More information about the functionality of CATCH can be found here.
We get lots of parents coming to see us at the hospital who have understandable anxieties about their children's health. Often, these anxieties stem from not knowing know what else to do when their child is ill. The CATCH app offers guidance and reassurance for parents to provide self-care for their children at home, without visiting the hospital.
Dr Kilroy, Lead Clinician for Emergency Medicine, Macclesfield Hospital