Say you have optimized your web for any browsers on earth, but you are not so lucky to buy a Mac and use its browser, Safari. There is some option you can do: Buy a Mac to get Safari, or borrow a Mac from a friend. And what will you do if you don’t have any friend having Mac?
You can try to view your web design using Safari with the help of Browser Camp, an online tool to emulate the look of your page using Safari browser and save its screenshot.
Another use is to save a shot of your design for your portfolios ^_*