The Mac filesystem can “replicate” files to unlimited places without copying them. This is not new. That is a fundamental filesystem function, probably even older than the company Apple.
DT calls that replication.
Unix calls that links (hard and soft). Available in the terminal.
Apple Finder calls them aliases.
About everything that DT does for organizing can be done in the Finder. The advantage of DT is the AI that is able to find connections between files and the search has many more options than Spotlight (but there are Spotlight alternatives).
I do not see any advantage of the DT database as a mounted filesystem. I am using DT instead of the Finder and run the scripts inside.
Some files are only indexed because of size or because they are automatically created be other programs. Inside DT there is no noticeable difference between imported or indexed files.
And you are not running scripts in the terminal of iOS because of sandboxing. On iOS you can access files inside DTTG because you have to do it that way. It is the only supplied function of the OS. On macOS you have more options (until everything is sandboxed too).