I find them aggravating because of my disability.
An acquaintance has made every light in their home integrated into Google's services. I have a mild speech impediment and Google seems incapable of recognising my speech as speech. "Hey Google. HEY GOOGLE. Hey Gooooogle! Turn off the lights." I'm sorry, I didn't catch that. "Hey Goooooooogle! Turn. Off. The. Lights.". I'm sorry, I didn't catch that.
And of course, when I gave in and used the switch, my host immediately came upstairs and chastised me for causing device errors to pop up in the network. Use voice!
Not terribly impressed, to say the least. And don't get me started on the bank's voice recognition system on the phone.
For what it's worth, which obviously isn't much, all my public rooms have smart switches as well as being able to be controlled by voice. And if someone needs to use the physical switch (they're all still uncovered and accessible) then that's a failure of my system not of whoever needed to bypass it.
The main benefit to me of smart is that I can automate transitions, so it's that much less likely that anyone will need to manually adjust the lighting.
In terms of understanding, it'll improve. I have a broad Scandinavian accent. My Alexa handles that just fine for the most part. It's not more than a few years ago most speech recognition struggled with that (I remember a phone booking line that insisted on recognising me saying "London" as "Birmingham")