You have several choices for backend storage of your wiki content:
A flat set of text files
A TiddlyWiki
An SQLite database
What are the pros and cons of each?
Flat text files
In this case, each wiki entry is stored in its own text (.txt) file. This makes it very easy to edit your wiki with a plain text editor as well as through the WikklyText wiki interface. In terms of speed, this falls between the SQLite and TiddlyWiki format.
TiddlyWiki
By storing your content in a TiddlyWiki, your wiki content becomes a self-contained wiki that you can open & edit it directly in your browser just as with any TiddlyWiki. The downside is that this is the slowest format.
SQLite
This is the fastest storage format. The downside is that it is only editable through a WikklyText server.
Don't worry too much about choosing the "right" format. You can always change to another format later via the wik conv command.
Summary table
Format
Speed
Self-contained wiki?
Supported markup styles1
TiddlyWiki
Slowest
Yes
TiddlyWiki
Text files
Medium
No
TiddlyWiki WikklyText
SQLite
Fastest
No
TiddlyWiki WikklyText
Footnotes:
If you want to ensure no formatting changes occur when moving content between the different formats, choose the "TiddlyWiki" markup style when creating content.