Yes, you have to hold the tokens in your own MEW or ledger in order to receive staking rewards and special privilege on NIOdex and also gain access to advanced AutoNIO platform features.
Trading on the NIOdex while holding NIO also gives automated market making rewards instantaneously and automatically as it will be hard corded into the Dex.

Specific details on the referral system will be released along with team token economics proposal next week. There will be details on different account types their advantages and referral system soon.