When you hide a tag you declutter your Tag List, but you can just show it again if you ever need to use it in the future.When you permanently delete a tag, Quicken removes it from the Tag list and from the Tag field of any transactions to which it has been assigned. You lose the ability to use the tag in future reports.
Also if your tag list gets long you can hide the ones you are no longer using for new transactions. You can also delete tags if you will not be using them for future reports. Per the Help,When you hide a tag you declutter your Tag List, but you can just show it again if you ever need to use it in the future.When you permanently delete a tag, Quicken removes it from the Tag list and from the Tag field of any transactions to which it has been assigned. You lose the ability to use the tag in future reports.
Also if your tag list gets long you can hide the ones you are no longer using for new transactions. You can also delete tags if you will not be using them for future reports. Per the Help,