I find the bookmarks bar an unnecessary and wasteful toolbar when I can just use the bar in the New Tab page (In Vanilla Chrome) or the Bookmarks menu to access my bookmarks. I use New Tab all the time. I have it set up to my most used sites via a custom extension I made myself, so it doesn't have a bookmarks bar on it, so I use the menu. But in Chrome OS or Windows, I don't have that same Bookmarks menu luxury, so a button would be useful.
You can't just enable the bar on those other platforms because if you have Sync enabled, it just ends up turning it on on all the browsers including the ones you don't WANT it enabled. I'd be much happier with just a button. I can't even install an extension to give me a makeshift bookmarks menu because once again, it gets synced to all the other platforms. Including once again, the ones where I don't need it enabled.
The Chrome toolbar has a vast amount of space available for stuff. Since it smartly dumps the outdated paradigm of having a separate search box (Which I can't live without BTW. One reason I hate using any other browser anywhere.) it has a bunch of space for whatever. Right now I have a line of custom extensions, Chrome to iPhone and Xmarks next to my Tools wrench. With plenty of space for more...
A NeoGaf extension that when clicked pops up a popup with Off Topic, Gaming, Subscriptions and a list of all currently opened NeoGaf tabs
A Twitter extension that simply opens Twitter
One for FaceBook too
Site to iPhone
Xmarks
And the toolbar version of my own custom Launch Pad that displays the same links in a popup instead.
But each one uses its own system resources. (Not much thankfully) And you can't create an extension that has more than one button. So in order to have a middle ground between clickable favorites on screen and a menu of favorites, I have a few custom extensions that take me to the most used of my most used sites. Sadly, Chrome does not sync custom unpacked extensions. I'd have to submit them to the Chrome store, but I don't see a reason to. They're not for public consumption. (I was able to get them onto the Cr-48 though through a cool trick involving Web Sharing, the File Manager on the Cr-48 and Chrome's "Load unpacked extension" feature.)