I woke up the other day to a notification that my LG monitor driver was installed, with a little window on how to use the on-screen crap.
Absolutely useless, since the buttons for the monitor are right there on the bottom of it, and probably easier to use than the software.
As to why people do install such software? It sometimes provides additional features, controls and settings. For example with touchpad you could set the sensitivity, hot corners, set the scroll behaviour the way you like it, etc.
With monitors you might get a better colour profile (P3 instead of just sRGB), I don't know. I don't use monitors like this.
> Connecting some LG monitors to a Windows PC may automatically install software that promotes McAfee subscriptions
I too have a LG monitor, but haven't booted Windows in some days, guess I'll stay put in my Arch environment until they've fixed this shitshow.