Shower walls are advantageous to tiles in the sense that they are made up of fewer parts. Typically, a shower wall will consist of three panels as opposed to multiple hundreds of tile pieces.
In turn, there is a lower risk of long-term damage to shower wall panels, meaning they are easier to maintain as well as install.
Ultimately though, it comes down to personal preference, as some people will simply prefer the look of tiling in their shower enclosure.