The back zip up makes it much easier to put the shoe on. Instead of lacing up the shoe every time, the shoe only needs to be adjusted once to size, and then the zipper used to get in and out of the shoe.
Suede is less weatherproof and gets dirty more easily than leather, since leather can be wiped down. Suede needs to be taken to a specialty cleaner and it's recommended to treat suede before wearing with weatherproofing to prevent water stains.