Why it so done? SyncDir tool - checkmark "Empty directories"

[AntonyD]

Open SyncDir tool, CHECK the checkmark "Empty directories", run the Sync action on a folder structure which indeed has empty dirs.
And just imagine that for some reasons we have MOSTLY empty dirs. BUT at the same time we must sync "heavy" directories - large files,
Thus the process takes a long time.
And the question is - why doesn’t this checkbox work as a toggle for the visibility of these empty folders?
Why, having unchecked this box, I should restart the process AGAIN and wait a long time again?
After all, at the end of the first iteration of synchronization, ALL empty folders are already known EXACTLY!
Total could really easily, if I disable this 'check'-option, also disable the visibility of these elements
in the already performed comparison iteration - in the opened list of synce'd items.
Why doesn't it work like that?

[ghisler(Author)]

BUT at the same time we must sync "heavy" directories - large files,

The function just makes TC find empty folders in addition to files. If you don't want files, use the wildcards field with a non-existing extension, e.g.
*.nofiles

why doesn’t this checkbox work as a toggle for the visibility of these empty folders

Because when unchecked, the sync tool ignores and skips empty folders just like it skips file types not included in the wildcards field - this makes sync MUCH faster when there are a LOT of empty folders/files of excluded types.

Why, having unchecked this box, I should restart the process AGAIN and wait a long time again?

Because the sync tool ignored and skipped empty folders.

[AntonyD]

If you don't want files, use the wildcards field with a non-existing extension, e.g. *.nofiles

Mmmmm, but I am not interesting in some exclude preprocessing for SyncDir operation.

Because when unchecked, the sync tool ignores and skips empty folders just like it skips file types not included in the wildcards field - this makes sync MUCH faster when there are a LOT of empty folders/files of excluded types.

+

Because the sync tool ignored and skipped empty folders.

Here both answers contain confirmation that Total, before starting the process of drawing elements in the SyncTool util, has already scattered in his memory what is what. And it created its own list for empty folders for example.
So the question remains the same - why I can’t control the RENDERING of elements in the synchronization dialog by clicking this checkbox about empty folders? Those: if it is marked, then the folder is "calculated" and drawn. The checkbox is unchecked - this means that empty folders are not displayed in the dialog.