I have used those portages both going in and coming out.  When I gave my rout to the ranger when picking up the permit they did not say anything but technically I see why some say it can’t be used to enter the park. I measured the time from the dock on Nym to Pine Bay Portage. It take me 10-15 minutes less time to go through those portages then go through Batchewaung.  One of them varies where the east end is depending on what the beavers are doing. There was a beaver dam across the middle of one of the lakes/puddles.  There not paved like the one Nym to Batch but there not bad either.