My users have been asking for functionality like this. There is one very active category on our forum, to the point where maybe 1/2 of the topics in the Latest tab are from that category and you start to miss other topics.
Muting the category doesn’t really fit our use case. I would remember to unmute the category but a lot of my users wouldn’t, to the detriment of the forum. What we would like is the option to browse all topics including the high-traffic category (on days when we have a lot of concentration and time) or all topics minus that category (on days when we’re a little short of either). Anyway, +1 for including this feature in core.