This can't be the first time you're seeing such use of Я? It's very commonly used in Western typography / graphic design as a symbol to invoke associations with Russia. It's not being used as a Cyrillic letter, it's being used a "think of Russia" and people unfamiliar with Cyrillic will mentally associate it with R so TETЯIS is easily read as "tetris". Even if yes, people familiar with the alphabet find it harder because the first reaction to Я is to in fact read it correctly.

Same with Σ being used as a "think of Greece" symbol that people from Latin-script languages are expected to process as E, leading to "brilliant" designs in GRΣΣK. Or how the Chinese character 山 would remind a Russian speaker of Ш so ПО山ЛИ would be easy to read.

As a Russian programmer, certainly you are aware of Elektronika 60 and Dorodnitsyn Computing Center? Regarding я, it is the same shape as R but backwards and feels exotic, nothing too complex there.