If you are unlocking your phone with that much of a chance of someone seeing your inputs (and subsequently getting physical access to your phone), that highlighting effect isn't your main problem. It would be easier to just make a mental note of the numbers as they temporarily display as they are typed.
The better way to address this is by making sure no one can watch your inputs (highlight or no highlight), make your pin longer so it's harder for someone to memorize in one shot, dim your screen so it's harder to see, and input the numbers quickly.
12-08-2019 11:44 PM