I don't see much point in asking for an office package in a job advert. But a lot of jobs do require use of these packages and the level of skill can be terrible in otherwise highly trained people. If you use the apps a lot you should learn how to use them properly, and a lot of people just can't be bothered.
I know it's kinda trivial, but I strongly agree with this. For example, inheriting a set of Word/Google docs where all the formatting is applied locally without the use of styles. So I can't turn on the outliner or generate a table of contents. Or not including a proper footer with page numbers in n/nn format so that if I print them out and drop them I know how to put them back together. Or having decent metadata in so you can find them on file system searches. Ugh.
One time, I was given an Excel doc with a bunch of numbers and totals and averages in. I updated some values, only to find none of the calculations changed. The creator simply hadn't used any formulas, or had pasted it all in as plain text from some other place!
Who's more likely to know (or be able to figure out, in 3.5 minutes) how to use Word text styles? The candidate who has room in the "skills" section for MS-Word, or the candidate who has actual skills to list?