I think the voice assistants on the phone are. They're funny for a few days looking for easter eggs then they get boring.
The Amazon Echo and Dot are useful though, especially when you connect them to your home lighting- we've got a few rooms rigged up now. I use it mostly asking what the weather is going to be like, what time is it, what's on my calendar, set an alarm, etc... I get it to convert Farenheit to Centigrade for communicating with folk back home.
all stuff I can do with my phone, but when I'm home I don't always have my phone on me. It's a nice to be able to just say out loud what you want, and it takes care of it. yes, the kids use it as a toy, asking for jokes and running the "meow meow" app to freak the cats out; but, I use it multiple times a day for real life uses.
It's certainly not an essential appliance, but it's a nice convenience. I never used the voice assistant on my phone though... what's the point, if I have my phone in my hand, it's quicker to tap.