no but it is better to be verified because some people will email u askingfor ur address and if the item goes missing u are not insured for the item.
I find the only benefit of being verified is that you can transfer money to and from your bank account, which helps in alot of ways say for instance you need to pay for a PC on ebay for lets say £300 but you only have £160 in your paypal account and £170 in your bank account, if you pay by paypal then the other £140 will instantly be transferred from your bank account, put with the other £160 in your paypal and a payment sent to the seller for £300, this is all done at a click of the button and you don't have to pay any additional charges. Also when you arent verfied you are only allowed to transfer to your bank account £500 in your entire life however when you are verified you can transfer as much as you like when you like.
Also when you have a verified account buyers and sellers look at you as a legit buyer/seller...just makes the process smoother.