@leocg Maybe it is similar, but when the tabs are grouped in the bar, You can see them and work with them at the same time. I would like to group e.g. ebay tabs opened and Google search tabs opened. Not using them in different workspaces. Or even better example. Searching for "vaporeon plush" and opening some in new tabs. And then searching for "pokemon cards" and doing the same. It would let me group two different searches. I am often getting lost with the tabs I am working with, because they are not grouped. Workspaces won't allow me to Ctrl+Tab. That's why I would love to see tab groups, this is very different from multiple workspaces, which could be used if You are not working with things at the same time. Workspaces could be useful, but they are not convenient if You are using tabs as I do. Different things that I work with/search at same time.
Also that's why I suggested tab colors, because this would allow me to do similar things, without grouping, but still, tab groups would be amazing. They are not really the same things as workspaces. They serve different purpose.
With those example, I hope You understand why I mean it's useful. This is really the only thing I want from Opera right now. More tabs customization. Colors, names, pinned tabs sizes etc.