Agreed, those things alone are worth it.
However, once I already had an Echo I started thinking of things that could be done with it beyond the trivial stuff.
For example I have been working on a tiny ESP8266 device that will sit behind or above the toaster oven in my moms kitchen. If the temperature is high for more than an hour or two, Alexa will say "I'm reminding you, the toaster oven is still on".
Total cost will end up being about $10-15, and requires no contact with or alteration of the oven, so it is a progressive enhancement rather than potentially making things worse or interfering with the basic function of the oven.
I could put a "smart switch" on the power supply and cut it automatically, but when things like toaster ovens are plugged in those switches are a potential hazard themselves.
It seems like automatic shutoff is something toaster ovens should all have, but clearly not all of them do. The same is true for ovens, stove tops, coffee pots, clothes irons, heating pads, tea kettles, electric woks, curling irons, etc.
Also seems like a better idea to follow the example of smoke alarms and use external monitoring rather than trust every single appliance to work properly.
I've considered putting something like an AMG8833[1] in a smoke alarm housing on the ceiling, so it can detect any appliance left on too long, but I'm not sure if it would work well in practice. Things like that are getting cheaper though, eventually it'll be possible.
[1] https://www.adafruit.com/product/3538