The number one feature I use Google Assistant for (and probably most people's most common usage) is to say "Hey google, set a timer for X minutes". If I dare do anything else with my phone during it's reply of "OK, five minutes, starting now" I risk the timer just... disappearing. If I can't count on it for one of the most commonly used tasks for phones I have zero faith for other things and don't even bother to figure out how to use it as more than an internet access terminal/music player.