It is common knowledge that the average business person regularly comes into contact with around 300 other people.

Average BNI Chapter membership 30

30 (members) X 300 (contacts) = 9000 potential contacts.

As you can see the first benefit is increased customer base, members are actively promoting your business with these 9000 people.

Other benefits include:-
Personal Growth
Public Speaking Experience
Education through regular chapter meetings and regional workshops