Internationalization state
China's international status is definitely improving now. When the children grow up, the world will definitely be a different scene. Going abroad is no longer the patent of the rich. Your children can go abroad as long as you like. By then, English will be necessary.
Multilingual skills
If China's international status can really advance by leaps and bounds in the future, Chinese will be as popular as English today, even more popular than English. Then there is no harm in learning English. After all, one more language and one more skill, anyway, the more skills, the more stable and smooth it will be in society in the future.
Multi-dialect skills
Even in the future, there is nothing unusual about English. Just like dialects in other places, understanding is a skill even if you can't speak dialects in other places. Maybe when others are plotting something with their "English dialect", it is a big problem whether you can speak English at this time.