It can be, later in a large book. But also, no readers other than Amazon's can display Topaz.

But I'm also a recent convert to the use of Calibre to manage my e-book library. Part of that package is a searchable content server, with which I can access my books over the internet. Downloading to whatever software/reader is handy.

Calibre can store and server out topaz files but it's not useful to do so when it's format locked to Amazon readers, and drm locked to a specific device.