why is scout rush so popular?

i see so many ppl scout rushing and wondering why is this? im playing only archer rush and everytime i see someone going feudal with 21 pop i know whats coming, wall my ressources build 2 spears and just raid with archers. in my elo (1200 - 1300) a scout rush is basicly just an invitation to go aggressive in feudal with archers + spears (spears even help breaking walls). also my elo is relativly low, i wonder why high elo players dont do the same? they are even better at quickwalling then me, so defending a scout rush should be easier. also scouts cost food so it delays castle time and you can only tech into knights. plus i wonder why do high elo player answer scouts with own scouts instead of 2 -4 spears and just rushing castle?