Blockchain is transparent. If you will make your own investigation you will find out that the most amount of BTC is concerned in limited number of wallets. Most of those wallets belong to huge corporations that invested in BTC huge amounts of money and now hodl it. So when press is talking about Bitcoin online transaction possibly they are mostly talking about small transactions. Can huge amount of small transactions effect on economic condition of developing countries? I doubt that BTC have such huge influence and can displace local currencies of developing countries. I think that banks of those countries will quicker provide CBDCs and displace local paper money on digital money by themselves.
Up until now, crypto transactions are still small compared to fiat transactions. So I don't see it as a replacement for fiat transactions especially that governments will still keep their local fiat, because they have the full control of its existence. We may see crypto adoption but it doesn't mean, it is going to displace the local currency of the country. Unless, the government itself declare that crypto or btc is their main legal tender.