There is indeed absolutely no reason to do this - and I'm personally anti-lawn (I prefer a nice naturally overgrown green space outside my home). But even I can get on the "this is awesome" train.
Fortunately this is opt-in. Imagine being that guy managing a fleet of these things mowing a giant golf course and three times a day just stop for no reason and start singing.
Sounds fun and all, but mark my words - after a year or two we will see some bug reports about lawn mowers randomly singing "Happy Birthday", and no one will know why.
I'd put the voyager probes as more lonely. Not to mention any number of defunct spacecraft that are still operating out there. They don't have off switches. Somewhere out there is a space probe periodically trying to phone home only to discover we are no longer listening.
""The oldest one I've seen is Transit 5B-5. And it launched in 1965," he says, referring to a nuclear-powered U.S. Navy navigation satellite that still circles the Earth in a polar orbit, long forgotten by all but a few amateurs interested in hearing it "sing" as it passes overhead."
This reminds me of the article "What football will look like in 17776?" a short story about football from the perspective of space probes. https://www.sbnation.com/a/17776-football
Now I want to look at a new robomower!