A comparable high-brightness 1080p display is about the same price [1], but uses a lot more electricity and from my experience with them, they have definite lifespan (2-4yrs, despite the 100k hours light lifetime claim) if they're running 24/7.
https://displaysolutions.samsung.com/digital-signage/detail/...
Watts are a unit of power, energy per time. Joules are a unit of energy. One watt is precisely one joule per second.
"Watts [per] hour" would be a change in power per time which is equivalent to an acceleration of energy and not an amount of energy.
To get an amount of energy, you multiply the power (watts) by an amount of time. If you want the energy in units of joules, you multiple the watts by the number of seconds in which the power was consumed. That's why kilowatt-hour a is a unit of energy; it's equivalent to one watt applied for one hour. One hour is 3600 seconds, so one kilowatt-hour is equal to 3600 kilojoules.
I believe you meant that the screens consume 200+ watts.