Property

The reasons for using properties are not real clear for beginners, and the criteria for choosing when to use properties are often a matter a of personal preference. The important thing is that use of properties is something that experienced developers consider a good thing.
 

Hi,
Mainly encapsulation and data security
encapsulation
You may not always using a field as like. You may do lot of process on it. In side property you can add logic to process[May be business logics] your private variable, then only pass it to the usres. These logics are hidden from users. This is really helpful once you have public fields and lot of users started using it. Later you need to change the logic of that public field. In this scenario, using property make sure that you have less dependecy to modify those fields which are already using by varuious users.
datasecurity
It's always a good practice that not give direct acces to any of your class levesl fileds. Only give indirect access to you fields so that crrok users won't get a chance to spoil your class members integrity. So class members will be protected in class with private accebility and any public values will be exposed through property, i.e. only getting the value of the field not able to interacting with real field.