The fact a country would ban Bitcoin has nothing to do with keeping the funds safe.
Well, that's not strictly true. If you keep your coins on a centralized exchange, web wallet, or similar, and your government bans access to these services, then your coins are effectively lost. A nationwide ban won't affect your coins only if you are the only person holding the relevant private keys, which should obviously be the default position but unfortunately we know this is not the case for a many users.
Of course that taken out of context is not true. It's cleared up in the next line. "Keeping your funds safe means keeping them on a safe wallet where you own the private keys or seed."
I hope that you can agree that the funds on centralized exchanges are not really safe whether bitcoin is banned or not.