The upside down table photo is not mortise and tenon, that's a slot for the design of the piece and is actually a modified through tenon. The second photo shows a box joint which is not as good as a dovetail, but probably what the designer wanted to you in the design. Those are all machine made, neither poor joints or exceptionally good ones. All that work is straight cut, and doesn't really determine how good a piece you are getting from those simple photos.