@nemobis more recent (2022 vs 2017) mention https://www.esri.com/about/newsroom/arcnews/property-tax-overhaul-in-finland-relies-on-advanced-spatial-analysis/ (warning: presumably promoting proprietary map data/software?) maybe only for residential structures/land?
Anyway value of land where data centers built seem like relatively unlikely to increase due to surrounding investment (what investment, in the middle of nowhere, or am I wrong?) vs say shopping centers and their parking lots, but if data centers can nonetheless motivate reform, glad to see it.