It seems these Generico filters can only be used within HTML areas and so you couldn't add one to an assignment title for instance. Not entirely true. Create the filter in the description first, then cut and paste into the assignment title. Granted, in their present forms, I have not gotten one of the countdown timers to work this way, but many of the other filter widgets do. I would imagine if all the graphic elements of a timer were eliminated, it could be made to work in the title.
The way I've used them in the past is in the description, with the description set to be displayed on the course page. When I also wanted to include a bunch of directions, etc. in the description, I placed them in tabs and tab items filters, and then placed everything but the countdown timer in a toggle button filter. Click to show everything, click again to hide it again. Helps eliminate long scrolls.