Aesthetics in maths

I am in an undergraduate programme in Maths (more in the applied side) and have some colleagues who are more into applied and some are more into pure. One thing that I noticed is that the latter ones use more frequently expressions associated with beauty and elegance with regards to maths content ( e.g. this proof is beautiful) than the former ones. I know that beauty is in the eye of the beholder, but i am wondering why that is the case.