What's the point with that quite lackluster story in Endwalker?

[Lauront]

The way the Ea shade puts it, reading between the lines, it's barely utilised even across the known universe, which itself is peopled by other similarly curious races:

Dew-deekh: Extreme differences can inhibit meaningful interaction, you see, and none more so than those which affect communication. Most entities, for example, cannot even comprehend our words.
Dew-deekh: You are rare indeed in your ability to do so. You avail yourselves of dynamis, yes? It is an impressive application...even if it is ultimately pointless like all the rest.

I think that's reinforced further by Endsinger's shock at the LBs drawing on dynamis. Plot-wise? Yes, it was mainly used in service of explaining why the Final Days were elusive and to provide a rationale for the Sundering. Otherwise, the main possible application for it is space travel in regions where aether is scarcer; it's essentially an alternative fuel source (albeit far weaker than aether.)