Having appliances beep with no way to stop the beep is a design fail.
I have a toaster that does this. When the toast is done, it beeps. Why? Dunno. They did it because they could, I guess.
But I don't like my toaster to beep. And I don't need it to beep. I'm quite capable of remembering for three minutes that I'm making toast and that it's going to be finished soon. If I could turn off the beep, I'd be happy. But I can't. I even tried dismantling the toaster and to physically disconnect the beeper. It turned out that this was so complex and difficult that I'd probably damage the toaster. So now I'm stuck with having the damn thing beep at me every morning, all because some technophile thought that beeping was a nifty idea.
Another offender is my washing machine. It beeps when it has finished with its wash cycle, to remind me to remove the washing from the drum. Fine, no problem. But, once the washing is done, it beeps three times every thirty seconds. Forever.
It is impossible to disable the beeps. The machine does not stop beeping until the door is opened. I don't like to rush to the machine to make it go quiet when I'm in the middle of things, especially since the machine is on a different floor, so I have to walk two flights of stairs. Yet, the beeps are loud enough to be heard through the entire house, driving everyone balmy. It should be possible to turn off the beeps. Or, alternatively, make the beeps back off. Have the machine beep a few times at 30-second intervals, and then back off to 5 minutes for a while and, thereafter, beep once every 15 minutes or so. None of these things can be done. Design fail.
Anova has made that exact same mistake. I've been unable to turn off the beeping from the app when cooking is done. To get the thing to stop beeping, I need to walk over and press start/stop, or power cycle the unit. I also encountered the beeping problem when the water level was a bit low. Incessant continuous beep. I added more water, which should stop the beep, but didn't. I could get it to stop the beep by pressing the start/stop button, at least.
For the low water condition, I can see the reasoning for beeping because it can't cook while the level is too low. But there is no excuse for beeping continuously forever. There is no safety issue either because, if the machine knows that the water level is too low, it will presumably be smart enough to not operate either the pump or the heater.
So, yes. Please make the beeps optional, so I can turn them off. Not doing customers that courtesy is patronising, at the least.