I don't see why not, brupacks do these brubox kits on the same principle and they work fine. http://www.brupaks.com/brubox/index.html
The seams will be stronger than they need to be to hold water I'd imagine. What you do with the brewbox is condition with the tap at the top so any excessive bulging can be relieved then it is turned to serving position two days before intended use so that it can settle out.
I still use the little 10L brubox as a small scale fermenter for trying out new recipes, as it takes up so little space and fits in a cool box to try and control ferment temp.