Difference between mainstream and special needs school

I wanted to know what is the main difference between mainstream and special needs schools.

My child has severe verbal communication difficulties but can talk some. My child won't always sit down. These are the only issues

I have been told special schools have the therapists which benefit children. However, the speech therapist which my child attends told me they only attend the special school once a week

If verbal communication is the only issue, but the understanding is there, are there any more benefits of sending my child to a special school, compared to a mainstream if the curriculum now is learning through play in year 1 and 2