I will add that I think they help with posture and stance as well. When I spar, I have guys that outweigh me quite a bit and they can't push me around because my core and stance is very solid. This also correlates to just walking around and having a solid posterior chain keeping your chest out and back straight- which is better for you.Oh for sure! Like you, you play rugby and need all the explosiveness, and athleticism you can get! But for a straight BB they could care less how they performed in sports!
Sorry man, I am not trying to beat this to death, I just want to emphasize how much squats help us.