So sorry for your chicken losses. I know how awful that is.
To answer your original question, there are a lot of good reasons to elevate the chicken coop, but the main one is that doing so increases the total amount of space available to the chickens. You are basically creating an "upstairs" (the coop) and a "downstairs" (the area under the coop, usually used as part of the run.) If your run is not roofed, it's especially nice to have it adjacent to that under-the-coop area for some much needed shade and protection from rain.
For any coop smaller than walk-in size (6' x 6', say), it makes sense to elevate the main body of the coop for cleaning purposes-- it's easier to reach in and clean something that's knee- or waist-high than something on the ground. A well-designed, elevated coop should let you open the cleaning doors and sweep old litter directly into a wheelbarrow. A coop that is ground-level, you'd have to shovel or sweep out, and *lift* everything into said wheelbarrow-- much more work.
From what I've seen, the prices for pre-made coops are ridiculous! That little one a few posts back-- $2000 for something that will hold, max, 4 chickens! My husband and I are building a similar coop-and-run close to twice that size (6' by 12') and it looks like our materials costs are going to run to about $700, plus a lot of our own labor. If you aren't able to build your own coop, it would definitely be worthwhile to look into buying the plans, and hiring somebody handy to do the work. You'll get a much, MUCH better product, for less money. These companies are running a real racket.
