Had Acorn (and it's desktop ambitions) lasted who knows what could have resulted from the ideas in that 3D demo - the spinning cube idea, now commonplace with Xgl and the like, is particularly ahead of its time. It has an uncomfortable resemblance to Microsoft Bob, though
IMO the main reason for such 'pointless' visual effects is to present an environment which is more visually inviting, particularly for less technically-minded users. If I showed my friends an Iyonix with no textures, anti-aliasing and running System font, chances are they'd laugh and never touch a RISC OS machine again. When the effects really get pointless is where they interfere with user productivity.