I may as well throw my two pennorth in.
Firstly let me make my own stance clear - I am a vinyl collector, when I used to DJ I only played proper vinyl and I spent the best part of my teen and adult life searching for and buying original vinyl and that "passion" was to the exclusion of just about everything (and everyone) else in my life. I re-mortgaged the house to buy records and consequently had it reposessed when I lost the job. Even spent the money I'd saved up for the revenue on vinyl too, the taxman was not best pleased to say the least Still do buy the odd record now and again but have calmed down the last few years. So for me vinyl, vinyl and more vinyl.
But .... the best collection in the world doesn't make a good DJ. No way, no how. A good DJ is one who knows how to put a set of records together for the specific crowd for which he (or she) is playing to. Be they rarities, common as muck, vinyl, CD, or even mp3 is irrelevant as long as the paying punters enjoy themsleves. In the context of some venues then original vinyl is just as important as the ability to put the set of records together, but not in most.
Phil