the search differs at some points, for instance:
tag:* returns all notes in the normal search and only a few notes in the 'link search' . Also the normal search looks in the whole note, the 'link search' in the title only.
About your example tag:*mar : a wildcard isn't supported in front of the string, only at the end like this : tag:gramm* This works even if the tag has spaces in the name.