Imposter syndrome which simply means that act of insecurity which is running in one's mind making them doubt their accomplishments in life and fear of being exposed. It is actually a concept in psychology as it involves mental interference.
The only benefit imposter syndrome can have in one's life is to keep such person humble or low-key. There are times whereby you may actually want to show off not knowing that showing off may cause your downfall, but imposter syndrome will refrain you from such attitude such that you don't feel arrogance or pride in what you do. It actually increases the level of humbleness and humility which also makes you submissive.
I believe imposter syndrome shouldn't be predominant in one's life as it may affect the level of one's self esteem making them loose confidence and timid in one's life. It is always advisable to be moderate. You don't have to be too proud and you don't have to be too timid. You should learn to apply both features when it's time is required.
Thanks for reading and I hope this helps.
I guess by IMPOSTOR is meant impersonation, which is a punishable crime in most nation of the world!!
But I would want to opine that whether it is a positive or negative on society depends on the INTENT of the impersonator.
If his intent is to take undue advantage of others, perpetuate crime of any kind ; then it is evil as it will impact negatively on society. But if the intent is otherwise, that is to prevent crime or to further general well being of a society as in many detectives and espionage security personnes ; it won't be accorded as negative on society.