That's NOT the same. I know that netinstall provides this feature.
What we are talking about is being able to put a script - say "default.rsc" or whatever it's name is - onto the router. After doing a "/system reset" (!) the router will clear all config and THEN execute this script.
One example for usefulness: After upgrading a router from 2.8.x. to 2.9.x things are "strange", as sometimes configs aren't upgraded fully (which is OK for - just too many changes...).
If this router is only reachable remotely you could now put the commands for a basic setup into this default.rsc, so after the reset the router would be reachable to do the rest of the config again, without having to get physically at the routers' location.
And I know this would be trivial to implement
(no, I'm NOT crying...)