You could soon be able to send texts via the Google Assistant from the lockscreen | Talk Android
The Google Assistant is a very useful tool when it comes to issuing voice commands to check the weather, power on the smart lights, or setting a timer. You can also use Google’s virtual assistant to make a call or to send a text although the phone would need to be unlocked to do so. This may not be the case for too much longer because Google is apparently testing the ability to use Google Assistant to send texts via the Android lockscreen without needing to unlock the phone first.
Even security risks apart (I suppose theoretically they can make it reliable enough) I imagine all these accidental texts people start sending to wrong people without even knowing :)
Before fingerprints and face locks came most people didn't even use phone locks to protect phone content. Most people I knew had their phones without password or PIN, main purpose of phone lock for them was to block the controls so they wouldn't call random people from their pocket.
@Alexander, the iPhone's facial locking has in the past proven trivially easy to circumvent. My experience with voice activation has been limited and unsatisfactory enough that I'd never rely on it. My current Samsung phone has a fingerprint scanner but it is very unreliable and almost always requires multiple attempts. (Granted it is an older phone model.) I certainly don't want Goocle listening to every word I say any more than I want Amazon listening to every word I say, which is one reason why I don't own an Alexa device.