1. Investors can have their funds traded in other traders account.
2. Funds cannot be withdrawn by the trader. Only investor can withdraw.
3. All funds are in the control of the investor.
4. Profit sharing between trader and investor ( this is set by the trader)
The disadvantage I see is that once trade is opened investor can't do anything about it. So select your PAMM trader with care. Some traders with small accounts are also pretty good