The review queues allow you to set up a tag filter, so we can filter our personal queue regarding our knowledge and/or preference.
I'm a bit confused by the review counter in the top bar. It can show up when there are items to review, but when clicking on it, it's possible there's nothing to review because of the filters I'm using:
Wouldn't it be better to show how many items are in the queue that fit our tag filter, instead of all of them?
Edit: A same behaviour might be required when the limit of daily review is reached. Then, the review counter seems to be useless. Wouldn't it be better to hide the counter in this particular case?