That depends on your personal thinking.
I'd rather pay 100 for a three year extended warranty than to pay 1000 in case that the panel fails after 15 month or 200 for a dead power supply.
If the display works flawlessly for three years the 100 ($, ₤, , whatever currency) obviously were useless, but who cares. Makes 2 more in a month for the display in a three year term.