This is a really cool idea and it looks to be made pretty well. American designed and made. Very cool. Of course if you use it as a storage closet and fill it full of junk it could be a pain in the ass to unload in order to switch to a trailer. Then again I guess that would depend on how much you use a trailer.
The dividers that are used as shelves will also divide cargo in trailer mode. It's water proof and for lower loads you can close the doors and lock it. Pretty cool idea for camping gear or small children (keeps the from wandering off).