I want to know the primary reasons people search for images.

You cannot use it for graphic designing. They are not raw images, which means that they are edited, compressed and recompressed, rescaled and distorted, which have long back lost its original color, size and clarity.
Content is not dependable and may very well be photoshoped to look original.
Most images are partialy or fully copyrighted, to which you will probably never know untill they find you.
Most images do not contain their original author/photographer and are likely stolen from other bigger sites, which probably hold the copyrights.
Filtered searches often contain disturbing material. Some time back I wanted to search for images of an Iraq war. What I got is a bunch of pictures of corpses and cut of heads laying out in the streets. Nasty.

How do you find Google Images handy, or as a matter of fact, any image searching?

I sometimes use Google Images to identify things. If I find a purple berry in my garden, I type "purple berry" into Google Images and see if any of the pictures look the one I have.

> Most images are partialy or fully copyrighted

"Fair use" laws allow certain uses of an image even if that image is fully copyrighted. So you may well look for stuff to integrate into your other works even when that stuff is copyrighted...

Thanks Roger, that's a good reason. It reminds me that I need to find out the type spiders in my backyard!

Also, thanks Philipp for the tip.