A storage facility manages your warehouse. You typically pay them per pick and to receive your goods. Then they make sure the goods are shipped to your customers every day.
A warehouse is a business that manages your warehouse. This means that when you order goods from your supplier, they are sent directly to the warehouse. They then put your goods on shelves. When orders are placed in your webshop, the warehouse packs these orders and sends them out. So, in short, a self-storage facility is outsourcing your warehouse. This can be an advantage if you don't want to touch that part of your business.
A warehouse typically charges per pick. This means that if an order contains three items, you pay for three picks. In addition, the warehouse will charge you for receiving your goods and shelving them, as well as for receiving returned goods.
One advantage of a warehouse is that they often have many webshops and therefore a high volume of freight. This means that GLS, DAO and PostNord, for example, pick up the goods daily and late at a warehouse. This way, you can offer more shipping options and late ordering and possibly still offer 1-2 day delivery.
We've been working with online marketing ourselves for decades. As the only shop system in the country, we have spoken multiple times at conferences such as Marketingcamp, SEOday, Shopcamp, Digital Marketing, E-commerce Manager, Ecommerce Day, Web Analytics Wednesday and many more.