It would not be a monetary entity, so that adjective does not seem appropriate to me. In any case, I believe that the activity of such a fund, if created, should be strictly controlled and confined to cases of an extremely serious and specific threat.
By contrast, an inflation target will not be the basis for an economic model when set by a central bank that has lost credibility due to excessively low inflation. For example, the declines in the potential growth rate and long-term inflation expectations occurred simultaneously in Japan.