Type 120 was offered without a tubing from the begin and stayed so with few recent exceptions.
Letting any adverse affects of the backing paper aside, the film is rigidly wound and by this protected.

Type 135 was offered in a metall box from the beginning and this kind of tight boxing stayed up today.
Within the cartridge the film is rather loose and more more succeptible to environtmental affects.

Very early in different parts of Europe different kinds of (rigidly wound) refills were offered, obviously to save on the cassette.
Where the tight box around the cassette was substituted by foil, this was seemingly done to save on material.