Yes and no.
Cargo ops may elect (at their option) to assign a SIC to the cargo flight -- so they can take advantage of certain FAR provisions which require a SIC (at least in theory):
- For example, if a SIC is on board, under Ops Spec C079 the flight may take off with reduced IFR minimums
- Another example, if a SIC is on board, then certain HazMat restrictions are relaxed
- Also, if a SIC is on board, then daily flight time limits are increased from 8-hours to 10-hours
The question is, may the right-seat log SIC when none of the above limited conditions apply? E.g., if a cargo flight is taking off under VMC, carrying no HazMat cargo and the duty time for the day is only 4 hours?
According to the FARs, the answer is no. But cargo operators like AmeriFlight argue that they can't always predict in advance when a SIC will be required, or at which leg(s) of the flight they may want to use a SIC. They want the option to have a SIC all the time, but no one will want to fly SIC if they aren't allowed to log the time unless flying under the limited circumstances described above.
So what they've done is to petition the FAA for an exemption, allowing a "qualified pilot" (per FAR 61 and 135) to sit in the right-seat and log SIC all the time, "just in case" they want or need to take advantage of any of the above provisions. And they get to charge for this "privilege".
How useless is the SIC time depends on the ops (and the PIC captain). If the ops has good CRM, and the SIC is really operating as part of a crew, then the time is very valuable -- IMHO much better (and cheaper) than someone buying block time to fly circuits in a 172. Otherwise, the SIC is simply ballast.