> Unambiguously, a system where the only code that runs is code that you explicitly run is more secure.
I don't think so? If I want to run a 3D modeling program and I download their executable and run it, it has access to everything on my system. All my local files, open access to my network connection, whatever's going on with my internal network, etc. If they want to read all my files and upload them, they can just do that. This is not true for web applications.
Programs that run in a browser are sandboxed and only have access to what web standards say they have access to. They can open a file select dialog to get a file from my machine with my permission, but they don't just have access to all of my files like a local program does. Web standards developers put a lot of effort into finding a balance between security and capabilities for new web APIs.
> What is the "Security Model" of the web
Unlike locally running programs, web applications don't have access to everything on the system by default. Interactions with the local system are intermediated by the browser. Usually the user has to approve access, or there are limitations on what types of access a web app can have.
If you head into your Firefox settings and select "Permissions and data", you can see what kinds of things given websites are allowed to access. Usually when they first try to use one of those APIs, the browser will pop up some kind of browser-level dialog asking the user for permission to perform that type of action (eg "access local devices" or "show notifications"). These are all examples of the web app security model (and there's a whole lot more that is not as user-facing).
Local applications on the other hand, do not have any kind of security model. The 3D modeling program I downloaded can just package up all of my files and upload them to their server, completely silently. That's way worse than what web applications can do!
> It's fine to just not have "Web bluetooth" actually. 800 "Partners" just don't need to be able to access that.
In fact, they don't have access to that unless you give it to them. Bluetooth access is gated by a permission: https://developer.mozilla.org/en-US/docs/Web/API/Permissions...