I also agree with tee-rex that Bitcoin isn't actually something you move outside a country, but the main thing is that it's more the fact that not Bitcoin is the problem here, but still fiat is.
If you wire money to an exchange, it will likely end up in a foreign country, and if people massively buy themselves into crypto, exchanges will move even more of their capital away from the economy. I think that's the main concern.
Not only regular individuals want to store their capital in other countries, but businesses as well.
That makes sense, and directly also explains why China is spending far less attention on their local crypto economy, while nearly all their focus is pointed at everything happening on centralized levels, and at the same time also the international markets. The logic basically is that as long as people in China keep exchanging crypto locally, capital with a high probability is going to remain within the borders, and that alone is already a valuable victory. I wonder if anyone from China atually knows whether or not exchanging crypto from person to person (P2P) is still allowed. Based on what I know from everything I read thus far, which I know of that it needs to be taken with a grain of salt mostly, nothing even hints at sanctions against P2P deals. The only thing that makes me doubt it somewhat, is the fact that if you sell crypto for fiat, you are basically a money transmitter, where if you don't have the proper licenses for it, it's an illegal practice. Can't exactly remember what Asian country it was, but a few people were arrested because of that.