Define field contents per filetype
Imagine the situation where you want to create a new custom column view where you want to add a "Comments" column. No problem you just set the field contents to plugin1.comments which gives you the comments for *.abc files. But what about the comments für *.def files provided by plugin2? Add another column or even a whole new custom column view? Wouldn't it be better to give the user the opportunity to select the field contents per filetype? It's already possible for other program parts like thumbnail view or quickinfos where custom columns are involved. Another example where this could be useful are information about archives. Imagine every plugin providing archive information like Ratio, Number of files and so on requires an extra column.