A consumer or junior engineer cares whether the toaster toasts the bread and doesn’t break.
Someone who cares about their craft also cares about:
- If I turn the toaster on and leave, can it burn my house down, or just set off the smoke alarm?
- Can it toast more than sliced uniform-thickness bread?
- What if I stick a fork in the toaster? What happens if I drop it in the bathtub while on? Have I made the risks of doing that clear in such a way that my company cannot be sued into oblivion when someone inevitably electrocutes themselves?
- Does it work sideways?
- When it fills up with crumbs after a few months of use, is it obvious (without knowing that this needs to be done or reading the manual) that this should be addressed, and how?
- When should the toaster be replaced? After a certain amount of time? When a certain misbehavior starts happening?
Those aren’t contrived questions in service to a tortured metaphor. They’re things that I would expect every company selling toasters to have dedicated extensive expertise to answering.