However what you don't get is a shared set of speed dials. You get more than one set which you can only see via 'imported speed dials'.
Yeah, you can goto the URL opera://bookmarks and copy the speed dials for the other device and paste them into your "speed dial" folder to get them on the current device.
It's the same idea with open tabs too. They don't sync directly. Tabs from other devices are just available at the URL opera://activity where you have to click them one by one if you want to open them on the current device.
What is the point of having an account and allowing sync, when it doesn't actually synchronise them ?
Opera feels that users want different speed dials and open tabs on each device and don't want them to be the same. So, there's no option to do so.