1) not water/weatherproof
2) easily stolen
3) won't fit in a four foot square picture window
4) if someone were to steal my matrix I sure hope they know xLights, linux, and Falcon Player because without those its a brick
5) you can't send xLights/LOR effects to a TV, only video
6) if I move and want to go big, you can't stretch a tv out for a bigger spot. you have to buy another TV.
7) one Pi can support up to 96 P10 panels using an octoscroller. Pi and octoscroller = $60, P10 panels are $8, you decide how many and configuration.
8) you never hear about anyone stealing one of those digital billboards (same technology) but tv's get stolen all the time.
9) try explaining to your insurance agent why you thought putting a new 55" tv in your front yard was a good idea, only legal in Alabama, West Virginia, and Arkansas.
I have more!