The wikidata advice although on the wikipage for a long time is probably the personal opinion of a long-term wikimedian and wikidata enthusiast. Not necessarily a considered view of it's value in the community.

The problem with all such well-intentioned edits is that they push up the last edit date and version count for little value. This has the effect of making it harder to spot things which DO need checking at a local level. 

Doing a basic join on value from OSM to wikidata works just as well as adding an additional key. The wikidata item already has an entry for the OSM key which effectively does this work already.