Why delete permalinks?

Oh, a beginners question. You guys (and Andrea or course) should be shock.

I've been wondering this for quite some time. I know that on a lot of systems, the ability to set permalinks is removed. Usually the excuse is that the number based permalink (ie /?=123 or whatever it is) breaks wp-super-cache

I don't on ours except for removing the number based option. All the other settings seems to work fine, even with wp-super-cache. Also considering that a few of our installs cater to non-english character languages, being able to use post number as a directory (ie /123) is used quite often.

What am I missing?