The difference is in the technology used to print the two. We usually refer to the regular photo prints as lab prints since they are produced by modern digital photo printers. The prints on canvas and art papers are produced with high end inkjet printers. For a more detailed explanation, please visit the following blog post:

Order HD Face Mounted Acrylic Prints
Printed on high quality photo paper and face mounted to 1/4″ acrylic with polished edges. Choose between satin luster or metallic photo paper. Included is easy to install hanging hardware in the form of a French cleat.