They are immersion breaking to those of us who actually know Forgotten realms lore. Those eof us who have read books and have played in this living breathing world for 30+ years now. Do portals exist in Toril, absolutely, are there 15 of them in one square mile....hell no. Think of them as Dragon age Aluviels (spelling). Extremely rare and very few and far between. To me this would be the same as putting in a modern railway system into the Lord of the rings setting. It makes zero sense and frankly ruins the lore of the world.
