Can someone explain the essence of goal line defence to me

It seems to be the flavour of the month on all these forums cuz it is mentioned everywhere
but i havent found somewhere that properly explains what it is

I think i have got the basics, audible to goalline from quarters or something
but why do people do it, what are its benifits


I just want to know how to set it up properly so i can lab against it and find its weaknesses and be able to break it down if (or most likely when) i come against it online

Thanks for your help

the basic setup blitzes one side of the formation an drops the rest into coverage. it gets good heat but you have to cover the middle to flats wit ur user guy

if you run it right, it gets quick enough pressure to make up for the lack of coverage. the setup i use, gets an insane amount of outside heat but you MUST user somebody to cover up the obvious quick pass.

if you want to know how to beat it. just have 2 reads that are super quick, if somebody users one of them then throw to the other. the first time i played somebody who did it i was so confused as to how get by it. so when you see it, stay calm, and just make your smart quick reads and you will be good