Local media assets

Can someone explain to me what the methodology and implementation of local media assets is in these need “experiences”?

How are custom posters, etc applied to the layout? Are they even applied at all? It looks like this new UX pretty much changes the entire way that posters, art, etc is displayed on the front end.

Posters are still used, e.g. in library view.
The detail pages and previews will however show the background.

In both cases, Plex will still use local media assets you’ve set.

So are the overlaid logos off when local media assets are the preferred option?

No. The overlayed logos are only used on the detail pages and when previewing items in a hub (the latter applies to the big screen apps).

Here’s an example from the library of the mobile experience preview (items displayed using their posters, no overlay):

And here’s an example of an item’s detail page (background image with logo overlay):