Is Minfilia always useless ?

[Riastrad]

So where is your fact that it is still used throughout the story? Give me the quest and details exactly when it's mentioned again in the MSQ that we are using the device to travel back and forth outside od the end of 4.55 when we are asked to find it and after the first time we head to the first? I'll wait since I have to leave for work soon

I'm not saying we are using it all the time. Iscah mentioned that canonically it is how the WoD travels between the Source and the First. Not me.

In fact, narratively (as opposed to what we can do for gameplay convenience) it seems like we don't really travel back and forth anyway, and when we do we use the Ironworks device and the mirror portal in the Ocular. We return to the Source through the mirror at the end of 5.0, and I think 5.3 as well. And IIRC it's specifically said that the Crystal Tower becomes known as the way that the Warrior of Light comes back and forth to visit.

I am saying that it is still possible without anyone other than ourselves activating it. Because, as I am sure you are aware, that particular G'raha Tia is dead. He's not doing much of anything anymore. Paplyamo showed us that magics dissipate after death. This one is still going strong.