It works just fine as a hempy mix, just make sure the bottom layer over the hole is something like perlite or clay pebbles or lava rock.
It’s just peat-perlite instead of coco-perlite, only difference is they add some extra lime to adjust the low-pH of the pro-mix. Good enough for nurseries, good enough to grow weed.
Pure perlite will hold a bit less water, but functionally your experience will be very similar. You can add extra perlite to the pro-mix HP, meet somewhere in the middle.