It's a ridiculous waste of space, even if you're on a high resolution screen.
I often use half sized windows so I can search for things while I work. Now, my results column is scrunched and hard to read because of the UTTERLY USELESS sidebar.
The "show options" feature did what this sidebar does much, much better.
Also, in smaller windows, the search box width is inexplicably shortened. So if you don't devote your entire screen to Google, you feel like you're entering search terms into a mobile device. Ridiculous.