Not all conductive fabrics block the same frequencies of RF or at the same effectiveness. We found the shiny knit silver plated fabric in the Adafruit shop to be the most effective across wifi and cellular ranges, based on anecdotal testing with various phones.
Layering different types of conductive fabric may yield better frequency coverage, much like having multiple active ingredients in sunscreen. LessEMF does frequency blocking tests on their textiles and reports a graph of their shielding performance-- our silver stretch is similar to theirs.
In our tests we also tried this pouch with NFC/RFID, and it did not block the phone from scanning a tag, nor did it stop an RFID entry tag from unlocking its door.
If you'd rather make your jacket pocket a cell dead zone, fold over the open edge of the pouch while it's still inside out and stick it in your pocket, using a whip stitch to secure the edge.