I work at a public library, built as a Carnegie library, where the year of its construction,1903, is represented on its facade as ’MDCCCCIII’ rather than ‘MCMIII’. Cursory examination of other same-era buildings suggests this was common practice.
I have my own suspicions as to why, but wonder if there is a definitive/definitivish answer.
Romans seem not to have used the subtractive method much. Maybe IX, but IIII was more common than IV-IIRC (there was a Cecil article about clocks with Roman Numerals).
I suspect the subtractive form was originally considered a form of abbreviation and inappropriate for non-ephemeral substrates like buildings and monuments. Using the subtractive would be akin to engraving “The Carnegie Libr.”