I think it depends on the extent of their needs. Some students can fit in nicely with mainstream education, with small amounts of additional help (eg, extra time in exams or note takers for those with dyslexia etc). However, there are those who need a lot more assistance than others, where their most important educational goal is to learn to live as independently as possible. They are unlikely to be suitable candidates for mainstream schooling, and need the extra guidance that can be given in SEN schools.
In India inclusive education has been made a compulsion . But I'm not sure of how far its practical at all times. Being a teacher myself , I still doubt this . But unarguably , if made possible , its great for a country and indeed for humanity .