(Answer rather than comment so I can use more space and formatting)
I hadn't heard of the American sense of "working holiday". Wikipedia treats "working holiday" as redirect to "working holiday visa" but Wikipedia has a system for handling ambiguity.
Getting your visa is only one small aspect of a working holiday. The trip will typically last 6 to 12 months. There could be lots of questions particular to working holidays which are not questions about the visa. We might have to wait and see. We could overload the tag with the "-visa" suffix to specifically cover it all though and say so in the tagwiki.
Saying the US doesn't participate in the program is one of those "100% true but 100% useless" answers (-: Though the US does not offer such visas, some countries (including Australia) offer them to US citizens. So US citizens do participate in the scheme. I believe there are even some special rules for US citizens to get working holiday visas since due to the non-reciprocal arrangement they are a bit special.
Your point of "tag is redundant if text appears in question" does not seem to be applied anywhere on SE!
I think the prediction of a "limited life expectancy" of working holiday related questions is astonishing.
All topics start with one question, should we not create new tags until at least two questions for a topic are asked?