Parking permits are common, from neighborhoods requiring them to park on the roads to universities using their own custom parking permits for students and faculty. Parking permits are so commonplace, that it makes you question why so many people are using them nowadays. this answer lies in the benefits that parking permits offer, not only to those issuing them, but to those they're being issued to.
Increased security - this is the most customary reason why parking permits are adopted. Take college parking permits, for example. Colleges do not want human beings beckoning up parking spots meant for students, and they definitely do not want students, or other human beings for that matter, taking spots designated for teachers. By issuing parking permits, they can control who parks where and keep things orderly and secure.
available Parking Guaranteed - there is nothing worse than getting to work only to find that there are no parking spots procurable. It just does not have to be work, it could be your neighborhood or your school, the point remains the same; not having anywhere to park when you need to is a pain. Parking permits relieve this by marking spots specifically for those who need to use them, keeping them obtainable of tourists or others who could take up all the vacant parking.
While these are the two main reasons why parking permits are adopted, the use of parking permits in communities brings a bit of disappointment along with it. Namely, what to do when you have guests over. For any neighborhood requiring their residents to use a parking permit, they should also provide a good several or four visitor parking permits for guests and visitors to use. After all, nobody likes going over to a friend's company only to find that they have nowhere to park.