There are various reasons why it’s a good idea to go for official repairs. For example official repairs tend to use official parts, meaning that they’re more or less guaranteed to work. They also come with official warranty so in the event that something goes wrong, they know what to do or at least can offer a replacement.
It also seems that with official repairs, there is no need to worry about your phone’s being hacked. In a paper put together by researchers at the Ben-Gurion University of the Negev, it seems that they have raised concerns about how going to third-party repair shops could lend itself to the possibility that your devices could be hijacked from a relatively simple procedure of replacing a cracked screen.
Basically these shops could embed a malicious integrated chip within the touchscreen display and from there record keyboard inputs and even direct users towards phishing websites. The researchers successfully tested out this form of attack using the Nexus 6P and the LG G Pad 7.0 devices.
What’s scary is the fact that these screens could be made to look like the real thing, meaning that the repair shop could be unaware that the screens they’re replacing could contain the malicious chip, or an intercepted shipment sent to official stores could also be affected. Also because this attack is file-less, security scanning apps won’t be able to detect anything wrong as well.