Because they can’t reach you when there’s a power outage to check that you’re warm. They can’t share boiled water with you when the mains break. They can’t invite you to a meal when you’re lonely.
They can mostly only ever wish you well.
Neighbors can provide these things if you’re willing to reciprocate. And you don’t have to be close with them, just friendly.
This stuff is valid, but a lot of it is more "be there in a crisis", which is not the day to day.
For me, the significant thing about having local community is the ability to throw stuff together last minute. Not every gathering has to have a spreadsheet of guests and canva invites and endless emails booking a band, a keg, whatever else.
A lot can and should just be "hey dudes, anything doing anything? Want to come over for a game/movie/whatever?" Those kinds of low-stakes hangouts are the real backbone of community, and they're hard to do if you don't have a friend group that's physically close by.