You still have to bring up your twitter page, but as soon as you type in @ all you have to do is type in the first letter of your contact. Sending a Direct Message is a little different. You type in a Upper Case "D" and insert a space after it, then type in the name of your contact you wish to direct message to. It does seem simpler just to select Direct message from Twitter. It would be nice if you could just "right click" your mouse to message to your twitter contacts.

you can type either a lower case or upper case d, I had mentioned in my comments uppercase. Also on the at messages only show the first letter of your contact which is pretty cool