Yes all flat screen LED TV's should have USB ports especially the newer ones that you buy today.
The USB port on the LED Flat Screen TV is useful for displaying pictures and videos without the need of a computer.
You can take your USB flash drive and plug it into a family members LED TV when you're at their house and show them pictures of your family or whatever you want too on the USB drive.
You can also give your family a USB drive full of pictures so that they can view them.
The pictures can then go across the TV as a slideshow or you can scroll through them and display one picture that you want for as long as you want.
I keep my pictures on a slide show but sometimes there might be a great picture that I just love to look at and keep it on the TV.
The USB port on your TV is so that you can put a USB flash drive into the TV.
From that USB flash drive you can view pictures and videos you have stored on the USB flash drive.
I will store pictures on flash drives and then I have a small LED TV in my office on the wall that I will play a slideshow of pictures on through the USB flash drive.
So you could put photos on a USB drive and then insert it into the TV USB port and display pictures on your TV if you want too.
You can also have videos on that USB drive to play on the TV as well.