Questionable benefits of thumbnails over mime type icons in list view

Often, especially with text files like ODT or PDF, but also most graphics files, I find it more difficult to find the file I am looking for by looking at the thumbnails in list view or column view. They are just to small to convey any information. It would be more useful to just use mime type icons here.
In the third view option (don't know what it's called), thumbnails make sense though, in my opinion.