The LG Q6 features a 100-degree front camera. The reason why you want a wide-angle lens for the selfie camera is because it allow you to capture and fit in more of the surroundings. A normal angle lens like one that many phone come with has around 82-degrees field of view. This means that if you take a selfie image or a group selfie, you need to hold the phone further away from you so everyone appears in the photo. Sometimes even stretching your arm won't give you the results you want.
This is one reason why LG implemented a 5-megapixel wide-angle selfie camera to make taking selfies and group selfies much more convenient and fun for users, but also to make sure your photos will turned out looking really great. Sometimes you also want to take a selfie while showcasing things in the background. For example, when I was in Barcelona Spain, I was in Park Guell. I went to the top most place and wanted to take a selfie while showing that beautiful cityscape of Barcelona. The problem was that my iPhone 5S had a narrow field of view, not a wide-angle one as the Q6. The result was that I had to hold my hands as far as I can from my face, and even then, the picture turned out not that great. I could have bought a selfie stick, but the thing is that with a wide-angle lens, in many cases, you won't need a selfie stick to take great selfies with a great surrounding background.
So great advantage right there for the LG Q6 and it's definitely a big plus for those of you who love taking selfies and searching for a great smartphone that is also optimized for that purpose.