Perhaps regarding this question i may help you
Advantages
	
sufficient time to study
	
No tension of school exams                 
	
  stress free study   
	
you don’t have to waste time studying one thing twice in both school and coaching                                                                                                                                                                                                                                                                                     Disadvantages  
	
lack of exposure
	
generally a student loses his hardworking capability as after joining dummy school they get stress free 
	
Getting more time slackens the student. Most of student wastes most of their time at home
	
As in school student from various coaching institute come so they can judge their progress with others but in dummy school it is not possible
	
you can atleast study a topic from very basic level which is not usually done be coaching                                                                                                                                              So it’s completely your choice but still I will suggest you not to join dummy schools. Instead you join your previous school and try to keep least possible attendance i.e. atleast 75%. Though i suggested you not to join dummy school but i regret joining my own school (which is not a dummy school)