It all depends on your personal moral compass. 2 ways of looking at it.
It's a service offered which you could pay for and get the followers this way. As a business transaction it becomes defined as something different. You require X and pay Y a fee to do this. However, generally speaking data from this method is of poor quality with very low engagement from the new followers/fans and more often than not, based in China or India and participants will get a small sum for following 'the client'. If it is quantity over quality you want then yes it will work 100%.
My own view would be to organically grow your followers as at the end of the day they will be real, interact more and if you look to eventually monetize your channels you will have more success. This is also backed up by the fact that I know of some brands who have used these types of services from my time in Marketing, have paid a lot, and received zero engagement.
Hope it helps:-)