You can still use MEDIA. So when you want to define an object set it’s type to MEDIA. If we were to add OBJECT too, then MEDIA and OBJECT would have the same meaning. What will happen then when you decide to edit that variable? Which type do we display as current? MEDIA or OBJECT? You cannot replace MEDIA type with OBJECT all together…
About the NUMBER - INTEGER thing: they are both there to be able to use the types of DB columns… might be helpful when you are using variables to store information taken from the DB or written to the DB, even if JS does not require it.