The example in the article appears to have the same screen size as a current-gen flagship phone. If you're going to keep the same screen, battery, etc and add a keyboard, it pretty much has to be bulkier.
Yes, but the point I was trying to make is that it's a design decision. It's perfectly possible to make a small phone with QWERTY hardware keyboard and flagship specs, even if no one is planning to do it right now.
With bluetooth keyboard and cover it even bulkier.