It doesn't., I say this to you as Russian.
And yes, you might want this wonder for relic slots and tourism boost even if you control no tundra tiles.
I will second this as someone who has written extensively on the Russian/Soviet military and has spent 'way too much time studying Russian terrain maps - if the Wonder was meant to be terrain-specific to the Moskva area, it woulds enhance swampy forests...
But the OP touches on a larger question, which is that terrain is very badly handled in Civ VI in general:
rain forest and regular forest are mixed in the middle of the map
tundra is supposedly a viable city start location for ANYBODY in 4000 BCE
No one in the game ever learns how to navigate on a river, so rivers have no effect at all on travel or trade
The massive variety of terrain and vegetation in the world can only be handled by having random Natural Wonders while the rest of the map is Generic forest, rain forest, plains, marsh, grassland, desert or tundra and all Resources are fixed in place from the start of the game.
Specifically to this topic, Tundra was home only to a very specialized (reindeer-based) nomadic lifestyle before the late Renaissance Era, and even then the only cities in Tundra area were on the coast - nothing inland could be supported before the railroads of the (in game terms) Industrial Era. Tundra should be exploitable and enhanceable only in the late game. Before that, you place your city on the nearest forest/forested swamp tile and extend city radius into the tundra, as, for instance, to exploit a Fur resource (see, for example, Vologda or Novgorod in Russia, both of which got rich on the fur trade, but neither of which are on the tundra itself: they are both in notoriously swampy areas (both Soviet and German troops referred to the area north of Novgorod as "The A**hole of the World" in WWII!)
We need both a lot more variety on the terrain and a lot more restrictions on the viable starting positions for cities in 4000 BCE on that same terrain.
If I were redoing based on its actual historical effects St Basil's, I'd perhaps keep the relic slots, but make it increase Religious Pressure and Loyalty from the city and boost both Tourism and Gold from Tourism from the Modern Era on.
