Definitely a cultual difference then - They were using Shu and Yugo's emojis because they were the only EN livers in the stream, and so they are the only livers they know and watch.

In EN streams, spamming the same text over and over again, even if it is something seemingly innocent like "Good Luck _", is frowned upon and seen as spam. It can also be seen as a form of sarcasm or trolling in certain contexts and will get you timed-out or banned.

Also, Youtube and Twitch uses algorithms/bots to filter out text comments even in chat, so to prevent being banned by the system (which has a history of filtering and banning people incorrectly more often than not), EN users are more likely to use emojis to express their feelings - Especially if the stream is in another language and they don't know how much English other people understand. And even then, sometimes the algorithm will ban certain emojis.

Many English speaking streamers in general have English only chats to make them easier to mod, so we are far more used to people using only emojis if they don't speak or understand English in chat.

Hashtags like "__#WIN" for tournaments are also seen as just a marketing ploy to many EN fans and are less likely to be used in chat. Tournament/Event specific hashtags are not viewed as sincere support of the liver by many EN fans, as in the west they are typically just used to try and sell you something (EN fans usually don't like ads). They would rather use emojis that directly support the livers themselves, not just the game/product being advertised.