Wireguard questions

[Terry Stanford 11]

I have never used Wireguard but now want to try it. I have installed Wireguard app for Mac OSX. Questions:

1. Does the 'kill switch' ("on demand") feature work reliably, as well as Eddie?
2. Is Wireguard now considered 'safe' to use from a privacy perspective?

I am not very technically-knowledgeable. I don't really understand this stuff but I read elsewhere on the forum that Wireguard assigns a fixed IP which is ALWAYS assigned to me when connected, unless I download new config files. That sounds like a concern for me after years of my IP rotating each time I connect via OpenVPN. Is my understanding correct or incorrect? I am surprised people are wiling to tolerate/use Wireguard if this is true!
Thanks

P.S. I just played with WG app and notice that, if you tick "on demand" (to activate 'kill switch'), you can't disconnect and connect to a different server! That's damn annoying! Maybe kill switch isn't so necessary when using WG, as the connection is more stable than OpenVPN?

[SurprisedItWorks 49]

Wireguard tends to be quite stable, yes.

The On-Demand feature
of the iOS WireGuard app (not talking Eddie here, as there is no iOS Eddie) is a bit flakey. You do have to explicitly turn off the connection that has on-demand enabled in order to turn on a different connection (and vice versa).  Not sure I'd quite call the feature a kill switch. I do generally look to see that it has enabled when it should have. 

Re privacy and the IP: this is frequently misinderstood. When you connect to an Air server, you will have an "internal IP" like 10.X.Y.Z that represents you in Air's internal network. It is only visible to outsiders if some program on your device reveals it.  This would typically be a browser sharing WebRTC information. Visit ipleak.net with each browser you use to see whether you have such a "WebRTC leak." This 10.X.Y.Z internal IP is a part of the config file from Air that you used to set up wireguard, and I believe you can replace it at any time by renewing the device key, creating a new config file, and installing that config in your client device. But if your browsers are set to not share this IP, it is not necessary. Worst case is that your browser does share it, and a website can see that someone (but who?) with this internal IP keeps coming back!  It is not traceable to you, so who cares?

This has nothing to do with the ordinary external IP that sites see. They will see your Air server's exit IP whether you connect using wireguard or OpenVPN, but they will not see your home IP assigned by your ISP.  So the privacy "issue" is quite minor and should not be a concern to most users. 

I leave it to you find, but Air has a decent discussion of this business somewhere on the site.  Perhaps in the FAQs?

[Terry Stanford 11]

Thank you. Sorry I should have said, I am talking desktop MAC OSX, I don't use iphone. 
Great explanation though, thanks very much