Opting wifi addresses out of public databases

I’d treat _nomap as a small housekeeping step, not as Wi‑Fi security. It may reduce some location-database exposure, but the basics matter much more: WPA2/WPA3, a strong Wi‑Fi password, router firmware updates, and a separate guest network for visitors/IoT if your router supports it. I would not hide the SSID; it tends to make devices shout the network name around more, which is the opposite of what most people want.