Why free float barrel is better for VSR10 rifles 

VSR10 rifles uses the stock to support the barrel and receiver however the injection molded stock is more often than not deformed to some degree. Depends on how much deformation is present, it can lead to misfeeding, nozzle grinding on HU chamber etc.
By using a one piece receiver of some sort, either glue the barrel to the receiver or make/purchase one, free floating the barrel can offer many advantages. Such as consistent feeding, smooth bolt pull etc.