@MartinSleziak I think I agree with your (and Willie's) judgement about copying wiki. But another problem is that copying directly from wiki will not be that useful as a tag wiki. Well, but then probably it is still than having nothing.

@JohnMa Yes, agree with that assessment.

The tag-info (especially tag-excerpt) is mainly to help determine what kind of questions the tag should be used for.

There are many tags where this is clear, so in those case it probably does not matter that much.

But I do not object to having some basic info and perhaps links to some resources in the tag-wiki, too.

It is somewhat different on meta - there I consider especially useful to collect a few basic links about the topic in the tag-info.

For example, if in some discussion I add a link to math.meta.stackexchange.com/tags/migration/info I know that if there comes some changes in the future the link will still contain information that is up to date. (And only the tag-info needs an update, not all posts on meta where this stuff was mentioned.)