Agreed. That's what the J-alert system is for. It sends out your basic "get to cover", "stay covered", "find high ground" type alerts but the NERV bulletins give you quite a bit more useful information on where else is affected and what impact that will have. Also worth noting that NERV supports a mobile app which can give you only the useful subset of notifications.

IMHO J-alert is for the first second and NERV is for the seconds after.