I think a lot of it is in the vast populations of some countries. Nigeria has 200 million people. So if only 1 in 10,000 people there listen to Radio China International, that's still 20,000 people, which might feel like a large audience to the broadcasters. In terms of influencing popular opinion, it will have a negligible effect compared to the vast effect of the internet, US culture, and so on. But governments aren't always rational about these things. Also, the framework for their international broadcasts is already in place, so it's not too hard to just continue what they have been doing and continue their shortwave broadcasts.