This is because the retailer has generated a shipping label (with tracking number) but the courier hasn’t yet picked up the packages, so they aren’t scanned into the system. The retailer’s shipping notification is automated so you get the email at that time.
For what it’s worth, I ordered a blanket from SmartPak on a Tuesday and it arrived that Thursday. I also needed to use the online chat for my order (I’m in Ontario and paying with a Canadian credit card, which appears to confuse their system) and the CSR who helped me was very fast and friendly in making sure my order had processed properly.