What to focus on, building apps for the browser or desktop?

Question

JavaScript

In my free time, I enjoy creating browser extensions, I recently started working on another project, but this time I decided to make not an extension, but a browser application. In the process of collecting information, I came across NW.js. This wonderful thing allows you to create desktop applications in HTML, CSS, JavaScript.
This topic is VERY interested in me, but there are a couple of unclear points that still do not allow me to completely switch my attention to development for the desktop.
1) What about updates?
So far, I have not been able to find a way to update "in the background", the only option that I see so far is to offer the user to manually download the new version of the program and reinstall it. With browser applications, everything is much simpler in this regard.
2) Will it be difficult to distribute a program from an "unknown developer"?
When starting a regular messenger for vk, my antivirus constantly starts a long file scan.