Why is the first tangible reward a t-shirt and not the product? If I was going to fund something, I would want to know my money is going to the product and not

Why is the first tangible reward a t-shirt and not the product? If I was going to fund something, I would want to know my money is going to the product and not merchandise. I don't think a YC pitch would go well if they said "And with the first $10k we're going to send out t-shirts to the first 1000 subscribers on the mailing list."