Kudo KingpinHi Tao, please see my comment below:
" I don't really understand why you need to create a separate column for filtering, since the time hierarchy itself has the field year."
"year" is just an example, it could easily be something else, in complex business analytics a simple time table is not enough, very often we need to create something else, for example, a filter for project milestones, payroll days, leap year, budget period, financial reporting, birthdays, HR days, etc.,.. real business scenarios
"The hierarchy can't be filtered by the added time columns unless you add the columns to the corresponding visual."
This is exactly the issue, it is a big failure by PBI because time intel table should work generically just like another tables, a data column must be able to filter the table, otherwise entire DAX logic breaks down. The app must follow its own logic. There is no MS document indicating time table work differently than others. Again, this is a major failure that MS needs to correct right away. Please discuss w/ your development team, I think they will agree.