Some people like to collect only originals, for purity purposes, like I don't collect fan-made or replica stuff. Saying you have a Gen1 collection that are actually from the 80s has more value (not talking financial value) than a collection filled with reissues. Plus there are people who do collect them for financial/investment purposes.
I have a lot of reissues because I prefer a nicer looking collection when on display and to play with, and they are a lot cheaper option to achieve that.