It is rarely even in cube lists so there is no surprise at all that it isn't played much
(The trading card game aspect came later.) While the colors of Magic were settled early on, the basic lands associated with them might not have been
Felidar Sovereign can win the game, while cards like Serra Ascendant and Righteous Valkyrie thrive when you have extra life points
The tokens Kykar produces are a good Polymorph targets, too, so you can cheat big creatures from your library into play
In a lot of cases, it's basically the white Craterhoof BehemothCraterhoof Behemoth (sorry, Moonshaker CavalryMoonshaker Cavalry)
I predict that the shockland sanctity will only increase as the game progresses, eventually reaching a point where they have as much inherent identity with the baseline game as basic lands have to this point