The problem is that it is very difficult to determine from the name whether a file is important or not. The same file extension can be used for very different kinds of files. Some similar files are very important. We might be reasonably sure that a file is unimportant but cannot know for certain. A mistake could have very serious consequences.
Edit: I would be very wary of deleting such files on my own computer which I know well. I know next to nothing about yours.