There is an ISTQB certificate for model-based testing, but I cannot understand what it is studying and who will need it?
Model-based testing is a word embracing different techniques to further automize testing and make it a systematic process.
The contents of the ISTQB course is not able to cover the very ambitious techniques existing today but gives an introduction to a very few ideas.
One of these ambitious techniques is to apply formal methods. Formal methods try to proof the correctness of the software under all conditions, similar to proving a symbolical mathematical equation for all values of its symbolic variables. This is difficult to reach for real world complex systems including hardware, software in all kinds of expressive languages etc. So a model is created and the proof is done on the model. In a further step the conformance of the model with the software and hardware is systematically tested.