You get priority packaging "free" under the condition that you pay priority shipping prices. Don't want to pay priority? Don't use their packing materials. Easy enough? More on reddit.com

This is a good question. Priority mail is really only supposed to make a difference on cross country items (example: NY to CA or FL to OR or NC to AZ, etc). This is why it’s important to pay attention to shipping zones. Pirateship offers good map for this if you google it. Basically if a package is zone 5, zone 6, zone 7, or zone 8, or going outside the lower 48, priority will take air whereas ground advantage will take surface. Priority is 1-3 days and ground is 1-5 days. There is no difference or upside in paying for priority mail over ground advantage when being shipped in zones 1-4. It’s processed together on the same machines, and they count on you to not know that there is no difference between the two in those zones. The only way it makes sense for non-long distance packages is when you’re able to use a flat rate box and save money. Ground advantage does not offer any flat rate boxes. That being said, the difference is minor, and although priority is supposed to be faster it tends to be less reliable than ground advantage. You’re really only talking about a 2 day difference at most for priority, even for cross-country packages. So my businesses all use ground advantage only. When customers want items faster, we use FedEx or UPS two day or next day air, since it’s more reliable and customers who want items fast tend to be willing to pay up for the guaranteed faster service, as opposed to the less reliable USPS priority. We only use priority mail when sending to Alaska, Hawaii, Puerto Rico, Guam, and any other territories, because in those instances ground advantage will take the boat, which takes 15-30 days, and UPS/FEDEX adds a lot of surcharges making it very cost prohibitive to not use USPS….we also use priority when the flat rate boxes can save money on very heavy and dense items. If you’re selling very high value items, some insurance companies require the use of priority and not ground advantage, or only offer limited coverage on ground advantage. More on reddit.com

I'm still trying to figure out why when I put some things in the RSS it says 3 day priority and 2 day ground. Even funnier when a customer notices and asks More on reddit.com

In general. Priority is faster. More on reddit.com