It’s possible to autocomplete tags when searching them in DT.
I keep a smart group named “tag filter” in the left side bar. When I want to find files with a certain set of tags, I double click the smart group, and type in the Tag is field.
This means you don’t have to remember exactly what the tag is to search for it. And you can easily save the results, which will automatically update itself when there are new files.
IMO text search can be much more efficient than sifting through a long list of tags, grouped or not. In terms of time complexity on the user’s side, text search is approximately O(1), whereas list selection may be something in between O(logn) and O(n).
Not to mention the dread I feel every time I have to use a side pane full of filter options …