The main thing is, if IVs aren't or shouldn't be explained to casual players, they won't notice the difference of the two Pikachus based on IVs.
I have played the Pokemon games for a long time, but I only learned and became conscious of IVs from Pokemon Showdown. Even in my latest two playthroughs of Pearl and Ultra Moon, I completely forgot that IVs were a thing.
The only way casual players could notice that IVs are doing something are in the Battle Facilities / Link Battles, with Pokemons at the same level. But they are going to think "I have to get better moves on Pikachu" or "I need a stronger Pokemon" long before they worry about the stats.
That brings me to the next point: IVs are not the only way your Pikachus can be different. Your Level, Moves, and Ability are substantially more visible and interesting differences. You would rather compare differences on cool effects and how much you trained your Pokemon, rather than stats from random chance.