Yes MoneyPak is basically an instant deposit into ones paypal account, once the MoneyPak is put in, it basically can't be charged back it works like MyCash.
The reason MoneyPak services were so popular at one time was because you can only buy and redeem them from USA paypals. So any big market users who wanted another form of guaranteed cash (no chargebacks) they used these.
Now however Moneypak is limiting, and banning, tons of redeemers because they aren't using the service like it's meant to be used..
Many people who are under 18 or don't have an established credit record won't be able to redeem moneypak cards (the majority of the forum). These services will redeem them for Paypal (subtract their fee for their time) and then send you the cash that was on the card via paypal for you. This allows you to accept MP as payment when you wouldn't be able to otherwise or turn MP cards you buy at the store into paypal. I hope that answers your question.
1. You send me the MoneyPak or My Cash code.
2. I redeem it.
3. I send you (or someone else) the value of the code via PayPal, minus fees.
4. I cover all transfer/conversion fees and send as a gift.
5. Money reaches you within two minutes.