Digital nerve blocks with SQ lignocaine have been in for a couple of years now for Paramedics and ICPs. Fascia illicia blocks are a logical extension, as would be wrist and arm blocks and perhaps costal blocks.
I don't see how that is a logical extension at all, because digital blocks and fascia iliaca blocks couldn't be more different.
A digital block isn't really a nerve block, it's just infiltration of some tissue with a small amount of local anesthetic. It doesn't require any special equipment or skill at all. Precise placement is unimportant and spread of the local isn't an issue. The volume of local is very small and there are no important organs or vessels in the area, so safety is of little concern. You could literally show a layperson one time how to do these and they'd probably have nearly 100% success rate in doing them on their own, with virtually no risk to the patient.
A FICB, on the other hand, requires special equipment (ultrasound and block needles - it can be done by landmark and feel, but rates of success with that method are inconsistent even among anesthesia providers who are adept at regional anesthesia and are doing the procedure in ideal conditions), and a fair amount of training and experience to achieve any consistent rate of success and safety for the patient. You need precise needle placement and proper spread in order to get a good block. You are injecting a very high volume of local (40ml is common) in the region of some critical organs, so the potential safety implications are not at all trivial. They aren't a hard block to learn by any means, but learning any kind of nerve block certainly takes practice.
The biggest problems with doing a FICB (or most other nerve blocks) in the field are practical. Like most blocks, patient positioning is important both for visualization and proper spread of the local. It would be very difficult if not impossible to do a successful FICB in a patient trapped in a car in a seated position, for instance, even for someone with a lot of experience doing nerve blocks. Also, these blocks take time to set up. You don't just place the needle, inject, pull the needle out and immediately do whatever painful procedure you are preparing for. It generally take at least 10, often 20 minutes or so for the local to spread and soak into the nerves and provide the anesthesia you are looking for. Finally, these blocks don't provide the type of dense anesthesia that you might be envisioning. It isn't like a spinal where the entirety of the lower extremity is completely insensate, or a supraclavicular block that does the same thing to the arm. A FICB that is working well covers the hip, femur, and lateral thigh pretty consistently, but beyond that, coverage and block density is quite variable, especially below the knee. Nine times out of ten you will still be giving these patients a fair amount of analgesics, even if the block works pretty well.
I did HEMS for over ten years and was present on countless MVC extrications, and now I do nerve blocks every day in the hospital. I can envision very little utility for these in the field. These scenarios are what versed and ketamine are made for. My prediction is that there will pretty rarely be attempted in the field, and when they are they will result in much longer scene times and low success rates, and will ultimately have little if any impact on patient outcomes or on the amount of drugs you have to give.