Seems to me the same problem would apply to animation or hide/show. You need to set the parameters in either case. Except you re making more "state" changes in the OBJ file with hide/show. Most AP buttons are "momentary". You push to "request" the mode from the autopilot and it will respond accordingly based on whatever the current mode is. Typically there would be indicator lights somewhere to tell you the "status" of the mode, i.e. OFF, ARMED, or ON. So, the button may animate when you push it, but usually will not stay depressed. The problem with having the button remain depressed is that it can be misleading as to the actual status of that particular AP mode. For example, if you push the NAV button and it remains depressed... is the mode now ARMED or ON? Unless you also have indicator lights or annunciators (preferably on the button itself), this can lead to confusion.