These folders are merely to allow you to reverse (uninstall) an update, and it is safe to remove them if the system is behaving.

I tend to switch the 'Date modified' folder view to 'most recent first', and delete any that are more than a month old.

They are usually around 1 - 2 Mb in size, and are usually compressed (that's why they show blue in the folder list).

However, as JiK says, if you are in any way uncertain, Micro$oft make them hidden by default to deter the unwary - so leave them alone! They don't take up much space, after all.