Yes definitely EncroChat gave criminals a false sense of security. I can't see how it was any more secure than using WhatsApp or Signal on a password protected iPhone or Android phone.
Ultimately, it turned out to be less secure than that because according to Wikipedia the entire thing got hacked and busted by European police joint operation. EncroChat's server was in France and had malware put on it by the police.
Yeah good point. They may well just have used WhatsApp on a cheap burner smart phone. You can get brand new smart phones for less than a £100 now as well not the thousands these things cost.