Hello Olga,
you are right, this feature is very usefull but there are some situations when this way is too time-consuming.
For example if I have a several hours long source file and I need to create several short files from different parts of it, there is much more efficient to create one temporary file from the all used parts in one long pass and then to create the result files from it.
That's why I'd welcome if you could to think about it.
Best regards
Jiri