How advanced is tiktok

I am genuinely curious how advanced the tiktok system is because I cannot figure out how did they manage to give the comment image feature to the exact people who don’t even comment in the first place. And i don’t think that it depends on the country, in my country all my friends have it except for me and they’re not posting comments so I genuinely don’t understand. Is the system so advanced that it somehow detected all the people who rarely comment ? I don't get it bro