Rooted devices are more vulnerable to malware attacks. Making changes to the original software codes increases the likelihood of introducing malware.
Voided Phone Warranty
Rooting your device will void your phone's service or warranty. The manufacturer will charge you for the repairs even when it is in the warranty period.
Risk of bricking your device
A bricked phone means a dead phone and is the same as carrying around a brick in your pocket. Making wrong changes after rooting will result in bricking your device.