Yeah, a lot of microcontrollers have integrated capacitive sensing (Atmel calls it QTouch, other manufacturers have similar). In that case a capacitive button is very near free, as you only need an extra trace that is reliable to fabricate and requires minimal extra soldering.

Capacitive buttons have some distinct advantages too, primarily being waterproof and nearly infinite durability. A lot of UI issues like OPs stove are likely poor software, there is no real reason why a capacitive button would need a 700 ms pause between actions. Now, the lack of tactile feedback is a more fundamental problem sometimes, but capacitive buttons can be great when implemented well.