Theoretically if done correctly then your REST service can be accessed by generic REST clients that don't know about your particular service.
Though generic client isn't going to know really what to do with your service. Aside from performing basic CRUD operations, a generic client would have no understanding if what any of it actually means. But, for example you can use code libraries that are designed to work with REST services in your client and not have to write as much boring "plumbing" code.
Though generic client isn't going to know really what to do with your service.
This is where hypermedia comes in. A rich set of standard media types allows your generic client to do useful things without knowing about any particular service.
Though generic client isn't going to know really what to do with your service. Aside from performing basic CRUD operations, a generic client would have no understanding if what any of it actually means. But, for example you can use code libraries that are designed to work with REST services in your client and not have to write as much boring "plumbing" code.