Unfortunately, the online planner is literally only that: a flight planner. It’s not an EFB, it’s just a web interface where you can generate some plans before you fly. It’s a little redundant, since the EFB also allows you to generate flight plans, but the EFB doesn’t have quite as much planning power.
It would be fantastic if the actual EFB was available as it’s own website, such that you could point an actual iPad at it while flying, but that’s not what we got. There is a wishlist item to make the EFB available on mobile devices, but it’s just a wishlist item so far.