I am fine with people having no degree and learning computer programming , but do not understand why people get masters in mechanical or electrical engineering

I am fine with people having no degree and learning computer programming , but do not understand why people get masters in mechanical or electrical engineering and then enter programming web apps..if its all about money why do they waste the mechanical/civil engineering seat at the university ? If argument is that they need to pay loans, then computer degrees should also be allowed to learn on the job and do mechanical/civil stuff ?