At the moment pretty much all Android phones have a voice assistant in the form of Google Now, save for the Pixel handsets in which they will be using the new Google Assistant platform. However if the rumors are true, LG could be getting a new voice assistant that could either be from Google or Amazon, in which the latter will be Alexa.
Google has previously stated that Google Assistant will be exclusive to the Pixel for now, but since we doubt it will be permanent, perhaps Google will want to kick things off with the LG G6. Alternatively Alexa could be a possibility, especially when you consider the fact that Huawei announced their plans to integrate the Alexa into the Huawei Mate 9.
In any case since none of this can be confirmed yet, do take it with a grain of salt for now, but of the two, which would you prefer?