Keep in mind that you want to have as little as possible starting up, but you also want to take advantage of your computer's ability to launch various programs without the need to do it manually. If you're still curious about some programs that you should let startup, apart from those mentioned in this article, then it's always a good idea to Google the purpose of that program and whether or not you should specifically disable it.
When a Spotify song is clicked somewhere on the web, it automatically opens up in the desktop application. It simply allows the Spotify desktop application to communicate with your browser.