Correct.
So yes, you could use it to hyperlink to the value of another element. The button element itself has no "value".
So you might do something like this, to get a URL fromanother element called some_element ...
var url = form_123.formElements.get('yourtable___some_element').getValue;
window.location.replace(url);
... or window.open(url) to open it in a new window/tab.
-- hugh