Call the library that is loaded, not the one that is not
A tiled blog layout, where posts sit in columns of uneven height and pack together instead of lining up in rigid rows, needs a layout library to do the packing. Browsers do not arrange things that way on their own.
Two names for closely related things
There are two well-known libraries here, by the same author, and one of them contains the other. The larger one supports several layout modes, and the tiled mode inside it is the smaller one. So a page that has loaded the larger library can produce that layout already, without loading anything else.
What it cannot do is answer to the smaller library's name. It registers a command under its own name and never defines one under the other. A page that loads the larger library and then calls the smaller one by name throws, and because that call sits inside the same startup block as everything else, it takes the rest of the block with it. That is the same failure pattern as how a design's features depend on each other.
The block calls the library that is loaded. Same layout, nothing added to the page.
Why not just load the other one
Because the alternative was registering a second layout library across the whole design catalog for a block that almost no page reaches. Every visitor to every design would carry the download so that a handful of blog pages could call a name they did not need to call. Adding weight to ninety-seven designs to avoid changing one line is the wrong trade.
It is the same reasoning behind how a stylesheet is assembled and behind how stylesheets are assembled: the page a visitor gets should contain what that page uses.
Posts without an image
One related thing worth knowing if you write posts. A post with no image attached used to render an image tag with an empty source. Browsers treat that as a request for the current page, so the page fetched itself a second time, and it produced a warning on every render.
The tile is now drawn without an image rather than with an empty one. Practically, a post you have written but not illustrated yet will look like a text tile instead of a broken one.
If you are thinking about running a blog on your site at all, the case for it is the place to start, and the argument for actors specifically is the follow-up. You can also connect an existing blog if you already write somewhere else.
