[bccdee]

If by "less sophisticated criminals," you mean "anyone too stupid to google 'encrypted chat app'," then I doubt they were ever much of a threat, especially for any kind of serious criminal conspiracy beyond selling a few baggies of drugs.

[ios14]

We would need statistics to assert one way or another. I suspect it’s the opposite: give people the means to easily maintain their own communication networks completely out of view of the government, and some will abuse it for other kinds of low level crimes beyond petty drugs: stalking, for instance.

I’d also bet that many criminals (those beyond petty drug pushers) aren’t even sophisticated enough to understand what’s at play here, and will use FB messenger regardless of the encryption implementation. In this case, offering a means to recover encrypted comms in exceptional, warrant-backed circumstances would only be of help towards criminal investigations.