My neighbors and school parents all coordinate via WhatsApp. The sky will not fall no, but if you don't join those groups you wouldn't know about upcoming HOA meetings, school events, important forms to fill etc.

Facebook is useful for bigger communities like moms groups. We found babysitters that way.

One of my social clubs tried to skip out of social media and was originally meeting in person, calling each other etc, but information just fell through the cracks as the club got larger.