I know. Typically I do not add this tag because of that. Only in very rare cases like a building directly at the border between two countrys addr:country=* is not redundant. From that point of view we should possibly remove addr:country=* from most objects.
There was this discussion about the redundancy of addr:country=* here. addr:country=* got described as “redundent but harmless” or even “redundant but useful”.
If you feel the need to do something about this redundancy feel free to discuss that in a seperate thread. I just think that if we include addr:country=* in OSM we should use it in a unified way as described in the wiki.