In addition to enabling an R-1 Visa recipient to live and work in the United States for two and a half years, it allows them to:
Bring their dependent family members into the United States and enroll children in local schools
Travel to and from the United States with no loss of visa privileges
Establish a legitimate path to procure permanent U.S. residency with a green card (note, however, that it does not guarantee U.S. citizenship)
Apply to extend the visa for an additional two and half years, for a total residency period of five years.
Further, unlike other visa categories, the United States does not place an annual cap on the number of visas that may be available.