A binary file is processed using a copybook mapping file with multiple records.
Lets say you need to save 200 values from each record to be processed later.
Using a test file with 2,000 records, it is determined it takes about 2 seconds to process and save the values from each record to variables using Filters.
However, the final version will contain 100,000 records.
100000 records * 2 seconds = 200000 seconds or
200000/60/60 = 55.5 hours.
Most likely this amount of time is unacceptable.
In this case DevTest may not be the best tool for this scenario.