You explained it all. The w's look like grass, so that's the connection. I guess you're asking why they use w's? Because わら is "wara" in romaji.
Oh, I didn't notice you said "I watched a YouTube video claiming that people also put lots of Ws together, because it looks like grass" with the order you said it.
It's not that they use w's because they look like grass.
They use w's because of "wara" and then the grass-related words come from w's looking like grass.
I guess you just misunderstood the cause-and-effect direction.
I see wwwww and 草 most frequently on Japanese streams. I saw a Japanese person being explained the meaning of lmao and they said “oh so like 大草”
wara = laugh
wwwwwwww = warawarawarawara
wwww=grass
grass = 草
LOL Meaning in Japanese
I wanted to know how to say “lol” or “lmao” in Japanese when I’m texting or DMing my friends, and I used the internet slang tag to find out. There are 3 ways listed on Jisho:
1.笑/わら
2.草/くさ
3.大草原/だいそうげん
I understand 笑, since the kanji means “laugh”. Later though, I watched a YouTube video claiming that people also put lots of Ws together, because it looks like grass. 草 means grass, and 大草原 literally means “big grass field” or “big grass plain”. What is and why is there a connection to “lol” and grass?