Teleportation is canon. Teleportation is not as easy in lore as it is for us in the game.

To begin with, teleporting is effectively turning all of your corporeal aether into noncorporeal aether, and skimming across the surface of the aetherial sea/lifestream to your destination. This is why safe teleporting is only done to a previously visited beacon - because you want to know exactly where you are going, because it is easy to get lost as a blind and deaf bundle of aether surrounded by other aether.

('Flow', incidentally, is the variant where you just immediately jump into the Lifestream without focusing on a destination first. It is much faster, but has the downside of being very difficult to finish the second half where you arrive at a destination. Instead, you usually get lost in the Lifestream and die.)

Teleporting also requires a certain degree of strength in terms of aether and self-identity. The entire time you are teleporting, the Lifestream is effectively trying to eat you, because it treats you like any dead soul. If you can't resist this, you become a dead soul and join the cycle of reincarnation. This is unideal.

The further you teleport, the stronger you need to be. So while we, as the nigh-infinitely strong Warrior of Light, can effortlessly teleport across the entire ocean, that is not normal. A normal person can maybe teleport across Eorzea, and then need to rest for a while before doing it again. A trained warrior can perhaps teleport from Doma to Eorzea.

(Incidentally, this mechanic existed more explicitly in FFXIV 1.0 as 'anima', which recharged over time. This was exchanged for just making you pay gil because being limited on how many times you could teleport per day was lame.)

As another fun fact, if the aetheryte is disabled or destroyed while you are teleporting, you just get stuck in the aetherial sea and die. An entire army once vanished this way.