x1 is cool/trendy/fashionable/in style/hip/chic/sophisticated-and-socially-desirable to x2 (observer) by standard x3.
Collecting wine may be sophisticated, but it is not cool; there is a component of social relevance and desirability to conform. This is not the sense of "cool" which means "impressive, awesome/awe-inspiring, wicked, really good, wonderful (either sense), acceptable (downplaying the intensity of the word)"; for that sense, use: xamgu or .u'enderfu.