Because of the anonymous nature of Bitcoin, its network does not require users to buid any network that is to say all you need is to hold some bits.
Can you explain this better, I am not getting any meaning to this.
Bitcoin is not a referral system.
If you mean bitcoin is not centralized? Yes, it is not.
Anonymous I mean it does not require physical contact and at that individual privacy is protected.
Bitcoin is not anonymous, it is semi anonymous or pseudonymous. You can track Bitcoin transaction on the blockchain but you can find it difficult or impossible to link it to the person that make the transaction.