I would never use gift myself, it's just not worth it as mentioned many times in this thread and others like it.
PayPal is a good service, and they, like any other service need to make money. Also, I would never leave myself exposed to fraud by using the gift option. It just makes no sense.
I think a lot if this 'net' or 'X' amount for shipping and then PP fee's might come from perception, in terms of how the price of something looks. Stores use this method all the time. You see a price that makes sense, and your in, then you get hit with shipping, and Sometimes other fee's, but at this point, you have committed to the item and just want it.
I think maybe the perception is that if you list a knife at $200 NET, it looks better to potential buyers than $225 to your door.
I spend a lot of time on the 'makers' exchange, and often shipping and PP charges are listed separately. Perhaps this is again perception in that the knife costs $500.00 and we commit because we separate the price of the item from what it costs to get it to our door....it almost becomes a charge we don't associate with the item at all, it gets separated and we feel
feel that we paid a total of $500, and not $550 or whatever the final amount turns out to be.
It can be a good selling tactic to the right audience.
I think that if it's within the rules, sellers have a right to list as they please, just as buyers have a right to buy from those that have terms they are comfortable with.