The short answer: cheap exports. However, that comes at a cost of making it expensive for Chinese travelers on heading overseas especially with EU, UK or US since they will need to pay more to exchange Euro / Pound or US Dollars when converting directly from RMB, since the Yuan is not strong against those major currencies.
Despite China having the second largest economy, their own currency is still weak against GBP, EUR & USD. Even though China is cashless for the most part, they still print bank notes (which are shit value) when you convert them as it's basically "pocket change" (so Western travelers have higher purchasing power than the Chinese):
By contrast when you exchange GBP, EUR & USD for Yuan (RMB): you still receive more than in their currency than a Chinese traveler would when they exchange RMB directly for GBP, EUR & USD when they're in a Western nation:
It would mean for a Chinese traveler, they'll be spending A LOT more money in the West (expensive for them due to lower purchasing power) than the reverse to an American, Brit or European when it comes of as "China is so cheap" flex just because they possess currencies that are worth more at face value.
The value of Chinese yuan is directly dictated by the Chinese government, in contrast to the other currencies you mentioned.
A stated raise in value would erode their national manufacturing competitiveness, which is a large percent of Chinese GDP, and hit most people in the country hard, instantly erasing a proportional amount of their savings value, which would threaten Chinese political stability.
1 usd to 6 yuan from 1 usd to 7 yuan means tge 1.5 billion chinese people holding rmb lose almost 10 percent of their purchasing power instantly and directly because of government action.
one of the upsides for the Chinese government is that Chinese people are very dependent on living in China, lending political stability and citizen retention.
This encouraged dependency is effective because it really is incredibly cheap aid convenient to live in china. USD equivalent of $1 meals, $100/month apartments, new 2026 EVs with the highest safety ratings in the world for only $8000, everything delivered to your door the same or the next day for free or nominal shipping costs, cashless society, national affordable healthcare, and many more.
Any declared raise in value of the yuan destabilizes the entire system and citizen dependency that the centralized government appears to be working very hard to establish and maintain.
Well, shit, maybe I need to learn Mandarin.
Ha, it's an interesting language, and the Duolingo course is actually pretty good, although I'm more interested in the writing system myself.
I lived in China for years and I'm gonna go visit some friends in a couple weeks.
If you're willing to teach English, living in China is a great way to save money very quickly while enjoying the affordability and convenience mentioned above.