For example, in case your Zenfone 2 gets bricked during the flashing process, it will not be eligible for warranty. However, keep this in mind that in case you are not at all confident about your technical skills, you better let a professional do it since the same rule applies to phones from all major manufacturers.
There are not a lot of things that can go haywire with the Android devices these days, but the steps need to be followed carefully. Keep in mind that the phone getting bricked from wrong flashing is the least thing you should be worried about.
Once the warranty is voided, even if your device faces certain problems in the future, unrelated to this incident, the warranty still remains void. However, this is a price that you have to pay for all the benefits that you can enjoy from an unlocked device.
People who know the various processes will reap major benefits from their unlocked Zenfone 2. Just keep in mind that unlocking the bootloader is final and you cannot get your phone back to a locked state, once you have done it.
Stay tuned for more updates on Asus Zenfone 2!