For certain things that don’t need to be in a TiddlyWiki instance and would just clutter up a TiddlyWiki instance …
If it is the kind of content that fits well in FeatherWiki, it might make sense in certains scenarios to manage that content in a small FeatherWiki instance and embed it in a TiddlyWiki (or wherever else needed) with an iframe.
For example, Sample BASIC Anywhere Machine Programs.