Doesn’t it require you to pay for the merchandise instead of having the buyer paying Printify directly like it happens with Redbubble?
If you want to offer a quick shipping you need to pay Printify before having the cash in your bank account, it might be just a couple of days of delay, still you have to pay upfront.
You also need a shop, like WooCommerce or Shopify, or use a third party marketplace like Etsy.
I’m not sure it’s the best option for someone who is starting from zero and has no money to invest. I will suggest it to someone who has some savings to invest in a self-hosted shop and in advertising ;)