Most of the time this prompt comes up it's actually for a genuine purpose, like spotify trying to find devices on the local network that can play audio, VLC looking for chromecasts, I saw my DJ app ask for local network and discovered it can discover my decks on the network and stream my library over the local network to it.
The problem is this prompt is new so the software doesn't show the user why it's just triggered the prompt and the user has no info to work with.
I need to turn on location access for all software on my system globally to read the battery status of a device over Bluetooth. These "could be used for" warnings are nice and all, but usually goes beyond what makes sense. Proposing that we need to press "be spied upon" just to view photos stored on your NAS is way out there
I'm sorry if people don't know what "access local devices" means but actively lying to them about the mechanisms is not going to inform anyone
I honestly don't think the average Google Chrome user knows what a 'local' device is, and we should go something more ELI5 "This website wants to spy on every other device connected to your network" or something
I get loads of them when I'm on a Netsweeper filtered network... pretty much any time any asset a page loads is from a blocked site (social media pixels normally).
This also got me on my partner's Macbook. For the longest time I couldn't figure out why I could access my local services on (Safari? I forget which one actually worked) but not on Firefox/Chrome.
I've seen it and at least in Chrome it seems to be treating all URLs which are based on an IP address as "local", regardless of the class of the address.
I'd be inherently suspicious of any website in the wild attempting to contact a bare IP address. Aside from localhost, my default assumption would be that such a website is either trying to circumvent my hosts file (or circumvent my other DNS configuration, e.g. pi-hole or DNS-over-HTTPS), malware trying to reach a command-and-control server, or malware trying to circumvent my adblocker.