Educational Technology is using technology to educate. The subject could be maths, history, geography, etc. Technology education is learning about the technology. It includes robotics, design, programming etc.
Although there are overlaps, generally, Roamer is an educational technology tool and Lego Mindstorms projects focus on technology education.
Students build Lego robots. Challenges usually concentrate on creating and programming a robot for a purpose. Often this offers the opportunity for engaging in studying topics other than technology, but the primary focus is understanding the technology involved in the robot construction.
You 'configure' Roamers for an activity that targets learning objectives in a variety of subjects. The educational value lies in the interaction between student and robot. In activities like the Solar System, the only technical thing the students do is press the GO button to start an activity. The rest of the activity is them reacting to the robots actions.
Obviously Roamer can focus on learning about technology. The Standard Roamers involve programming based on Logo and this can pose a number of technical challenges. A robotic curriculum for older students is under development.