The biggest problem with USDA zones is that they only tell one thing - how cold it gets in the winter.
I am looking to move to a zone 5 location which will allow me to grow some things that I cannot grow here in zone 8 because we do not get
enough summer heat. Two summers ago, the maple leaves turned red before the tomatoes did.
USDA zones are useful only for determining which perennials will survive the winters. Nothing else.
We are not looking for an exact address, or even city/county.
Something like: "Pacific NW, west of the Cascades", or "Eastern TN, Appalachia" is often enough to give people an idea of growing conditions that somebody needs to deal with. "Heavily shaded", "steep slope", "boggy flat lands" and other descriptive phrases give us more information than "Zone 6b".