I set alarms and reminders.
I ask how to say thing in various languages, then ask those words in that language to see if Google say the right definition. I check facts.
Fact retrieval performance varies a lot and is a good test of an assistant. Alexa is very good, because it can't rely on a screen (and it seems a lot of people work on making it good at knowledge type stuff). Google is also decent most of the time. Apple often defaults to "here's what I found" which is useless.