If one has a bank account, or wishes to use their bank account - then they probably don't have this issue to begin with, because coinbase also allows one to cashout to bank accounts. However not everyone has a bank account, and more so not everyone wants their bank account backtracked to bitcoin.

Now about the fee's... they vary - and thats actually a secret very few people understand how to game. When you first create an account the transaction fees on your trades are just under 4%. The more you trade, the smaller that percentage gets until its under 1%.

What I have learned is with a little patience, you can actually sell your bitcoins for more than the value of bitcoin is - AFTER you reach that less than 1% mark in trading. So its actually possible (and I have done this several times) to end up cashing out to paypal, and having more than the trading value. Say a coin is $4000, you can manage to get $4100 which after cashout fees (2% +$1 USD for paypal fees) you end up $4012.

Figuring out fee's and how to game the sells is the hardest part, but after you do, I honestly think its the best way to cashout.