Maybe some people can only afford a bard made by gsi due to price.
I can't imagine that scenario. Shops around here are charging at least $400 for a new GSI board. Like NJSUrfer42 said, they are generic shapes that will work, but wont hold value and wont be anything special.
Around here the used board racks are FULL of lightly used board hand shaped boards, locally shaped (if that's what you want) non-generic boards for less than a new GSI board. Spend an afternoon cruising the used racks and see what $300 and some bargaining will get you. Choose wisely and the used board will cost less to purchase and will be worth more than the GSI board within a year of normal use. So even from an economic standpoint (if that has to be your determining factor in selecting a board) the GSI would be a worse choice.