Ultimately this is about perceived control, the paraphrased saying goes “if you outlaw encryption only outlaws will have encryption”. Legislation won’t reduce the use of encryption by criminals and terrorists, it will however allow the government and law enforcement to say “you have encrypted chat software, that’s illegal, therefore you must be doing something illegal”. However, that wont necessarily translate to prosecution, it’s only the perception that matters.
Pandora’s box may have been opened but governments will always find a way to “control” their citizens, usually through fear.