You may use concatenate for different granularity - it's ok. For instance if you have two same tables - one for months and one for weeks, so you can easily union them. No need to use link table. But, if your tables match only with few fields (customer + country) so the better way is to use a link table with a key.
Looks like the goal. One more advantage of concatenation: You can use it instead of JOINs for avoiding record multiplying (if you get such cases during tables join).
