IDE Inspector API version checkboxes

What is the real purpose of the API version checkboxes for API 1 / API 2 in the IDE second pane inspector, the one with the gear icon ?

I’ve thought that they force the use of API 1/ 2 commands syntax in the class/control code, but seems that it’s not the case, at least for “value” property in textfields that is still recognised even unchecking API 1.