I like the idea of incorporating locally available microbes but forgive my ignorance: is it safe?

Mostly to see what it's like. The businesses selling starters focus on historically interesting, important, or notoriously good starters (like the "San Francisco sourdough", or the oldest known starter in the world, salvaged from an Egyptian tomb). I've done my own wild starter, and my daughter has also done wild starters (in her case, she made a rice bran starter for making Japanese nukazuke pickles).

So mostly, it's the academic interest.