I may be wrong but I kind of remember having read somewhere that Scaled is there for compatibility with the VCL; i.e. it does nothing. I was wrong; see below after "ETA"
But to make sure just try to find where, if anywhere, either the property or the field are read from/written upon.
Setters for size/position and similar methods are good candidates, as well as methods which create controls, like CreateForm(), etc.
ETA: I was wrong. doing a:
grep -Fir "application.scaled" *
in the LCL directory results in:
buttonpanel.pas: if Application.Scaled and AParent.Scaled then
include/customform.inc: if Application.Scaled and Scaled and (Monitor.PixelsPerInch<>PixelsPerInch) then
include/customform.inc: if Application.Scaled and (PixelsPerInch<>Monitor.PixelsPerInch) then
include/customform.inc: if Application.Scaled and (ParentForm<>nil) and ParentForm.Scaled
include/customform.inc: if Application.Scaled and Scaled and (NewDpi<>PixelsPerInch) then
include/customform.inc: if Application.Scaled and Scaled and (Monitor.PixelsPerInch<>PixelsPerInch) then
include/hintwindow.inc: if Application.Scaled and Scaled and (Mon<>nil) and (PixelsPerInch<>Mon.PixelsPerInch) then
include/customdesigncontrol.inc: if Application.Scaled then
include/customdesigncontrol.inc: if Application.Scaled and Scaled then
include/customframe.inc: if Application.Scaled and (ParentForm<>nil) and ParentForm.Scaled
which is just a minimum; there are probably more instances of use in there and in "./components/" and elsewhere.