When computer effects appeared in movies they were embedded between scan and record process. These tended to be pricey and often long and cumbersome. A digital movie process changes this entirely. The dpx files ARE the negative. They are first class citizens. Every Visual Effects House has access the to the original negative. Quality can be maintained.
Since the scan/record overhead is gone and material can be exchanged via commodity shuttle drives a new field of visual effects becomes possible. Since there is no film weave split screens became almost ubiquitous. Since the editing equipment also had shake software installed it was possible that many visual effects shots were executed by the Assistant editors. In a digital file workflow visual effects become a much more natural part of the editorial process.