does it face any performance issues?
Yes, touchscreen failure.
IPhone 6
Normal use of the device can cause the logic board to flex internally, which strains the touchscreen IC connectors and leads to a degradation or outright loss of touchscreen functionality. 
when was the iphone 6 released in australia UNANSWERABLE what is this machine? A smartphone designed and marketed by Apple Inc. when was it released? September 19, 2014. what generation of phone is this? Eighth
wiki:1692558
IPhone 6 [SEP] Touchscreen failure ("Touch disease")
Touchscreen control components on iPhone 6 logic boards have insufficient support, including a lack of underfill—which strengthens and stabilizes integrated circuits, and a lack of rigid metal shielding on the logic board unlike previous iPhone models; the touchscreen controller is instead shielded by a flexible "sticker". Normal use of the device can cause the logic board to flex internally, which strains the touchscreen IC connectors and leads to a degradation or outright loss of touchscreen functionality. A symptom that has been associated with this type of failure is a flickering grey bar near the top of the display. iFixit reported that this issue, nicknamed "touch disease", was a byproduct of the previous "Bendgate" design flaw because of the device's demonstrated lack of rigidity.