When organic material such as food scraps and green waste is put in landfill, it is generally compacted down and covered. This removes the oxygen and causes it to break down in an anaerobic process. Eventually this releases methane, a greenhouse gas that is 25 times more potent than carbon dioxide.
Also, landfills are big, gaping piles of trash. Imagine moving to a new neighborhood and there being a landfill smack dab in the middle of it. You have to realize, it can stink for miles and its not very neighborly to have a big pile of trash in the neighborhood.
And lastly, it pollutes the air. If phones, tablets, and other electronics are in a landfill, (and they are) it releases radioactive waste into the air and soil, making the landfill, even after trash is gone, unable to grow plants or inhabit life at all.
I know you only asked for the eyesore part, but I enjoy answering these types of questions so I went all out. Hope this helps.