We can't discount the valuable consulting services provided by a solid mom group. There is a universal element to raising kids that isn't confined to geography. My friends and I will be going through the same thing, just in different states. Mom friends are your real-life Google for parenting. What's the going rate for the tooth fairy? Is anyone else struggling with this newfangled way of doing fractions? Does saying "newfangled" mean we're officially old? How do we feel about these sports bras? The line of questioning gets more complex as our kids get older, and there is seemingly no end point for leaning on each other for answers. In other words, there's no expiration date for parenting.
With high school friends or work friends, your relationship likely exists in finite terms. You graduate and you move onto other jobs. But there is no end point for mothering. There are many seasons of parenting, and that kind of continuity can really tether you to your mom friends.