Just to say I strongly disagree on your characterisation of the use of this ID as a "hack" and that it should be actively discouraged. Not all countries are as fortunate as others, and having comprehensive coverage of all the relevant sites on Wikipedia with unique identifiers from state bodies is a massive hurdle to overcome for many of us. Assuming that the whole world can meet you at the standard you are accustomed to is incredibly unfair, and dismisses the difficulties many countries face in this regard.
In the Irish context we have found the P2186 a very neat solution to a systemic issue we face regarding data on Irish monuments and other listed buildings, and in the 4 years since we started using those IDs with Monumental, it has not only facilitated a huge amount of participation, but the Irish system has not been updated to a point that we have another system of unique IDs to fall back on. And this is an EU country with supposedly all the benefits that that entails. An alternative "scalable solution" has yet to otherwise manifest.
Fair enough if you don't like a particular system of IDs, but I don't think completely writing it off is fair on those for whom it has been incredibly useful.