I can't believe that someone would just trust Alexa to order 'diapers', at the very least you'd specify the brand and the size, "Alexa order pampers for a 10 kilo child".
Someone else mentioned USB cables and I don't think I would trust even that to Alexa. "Alexa. Order me the cheapest 1.5m USB cables which isn't of questionable quality, but keep it below $5."