Śākyamuni Buddha is, of course, the buddha of the sahā world. Thus, by elevating the status of Śākyamuni Buddha to cosmic superiority over all others, the importance of this world is also stressed. Here we can see one of the main themes of the Lotus Sutra, evident in virtually all of its teachings — the importance of this world and of life in this world. In this story it is to the sahā world that the Stupa of Many Treasures Buddha comes and it is the sahā world that is purified to receive all of the buddhas from other lands. The worlds of the other buddhas are described as wonderful in every way, but the buddhas leave those marvelous worlds in order to come to the sahā world and pay respects to its buddha.

In a sense, we may think that, since it is in it that the cosmic significance of Śākyamuni Buddha is revealed, praise for the sutra is always also praise for Śākyamuni Buddha. At the same time, because this is his world, praise for Śākyamuni Buddha is always also praise for this world.

The jeweled Stupa in which the two buddhas sit is a kind of tower and the character has that meaning in Chinese. The image of such a tower, surrounded by the buddhas and bodhisattvas from all over the universe, is clearly an axis mundi image. Such images always, I suppose, give importance and power to the place where the axis is located, in this case to this world and its buddha.
A Buddhist Kaleidoscope; Gene Reeves, The Lotus Sutra as Radically World-affirming, Page 181-182