As someone who creates software for the education space, in my experience Comic Sans is picked in schools because it has the 'a' in the shape that you actually

As someone who creates software for the education space, in my experience Comic Sans is picked in schools because it has the 'a' in the shape that you actually write an 'a'. This helps when teaching primary school children. Some schools will got out of their way to buy special fonts but most will default to Comic Sans because it is ubiquitous.