There are plenty of reasons to root without installing ROMs. Freezing or uninstalling bloat, as you've mentioned, for starters. Also there's having a fully functional Greenify, all apps enabled for dual window, then, one of my personal favorites, having my phone automatically switch GPS high accuracy on/off based on which app I'm using, and then any number of apps that require root that add some functionality to your phone.
I have my G3 handy if I ever want to play with ROMs, but I legitimately like the LG UI so I'm keeping this on my phone and I'm glad we now have root so I can fine tune my phone.
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