It's a nice time saver if you would like the HTML editor to automatically add quotes for the attribute values while you are typing.
To set this option select Tools->Options. Check Show all settings. From the left pane select Text Editor -> HTML -> Format and check the insert attribute value quotes when typing checkbox.
Now as soon as you hit "=" for the attrib value, editor will insert a pair of quotes and show the intellisense for the values accepted.
Select a value from the intellisense and press enter/tab. Cursor would jump out of the pair of quotes (you will have to hit the arrow key after entering the attrib value, if it doesn't show up a list of values).
SDET | Visual Web Developer