In blogs (or sites in wp-newspeak) with a lot of categories and subject matters, sticky posts can become a major administrative burden, especially on news based sites that need to keep posts in the public eye within their categories only.
Sticky posts need a scheduled "de-stick after/on ..." function.
As of today, a simple example could be Remembrance Sunday (11th hour of 11th day of 11th month) 2 minutes of silence to remember all those who dies during the two world wars.
A post could be stickied with an auto de-sticky to occur at 11:02am - this would actually be a time-critical desticky due to the respect of the remembered issue, and that some veterans / dependents could be offended if the sticky was not removed in a timely manner.
The above is a very simple but widespread public interest example. There are thousands or regular uses that this would be needed for.
Additionally, the sticky function could be used to resurrect posts to sticky for a period long after their original posting date - such as a simple commemorative date post - a revered national leader's birthday or whatever, or a reminder that tax returns must be filed by X date, and so forth.
In terms of page ranking and other SEO, this would give a slight boost at least to the site or category home page, by having the lead content change, Search engines would pick up the content change and see it as active maintenance of the site ... but that's a side benefit compared to the functional usefulness to readers.