The markup for tables seems to be an advanced feature. Not all wiki engines even have such a thing, and different wiki engines differ considerably in how complicated table markup they offer, from just simple tables to full control over the presentation.

Depending on the use case, it can be also better for a wiki site to use an alternate markup for tables, like the CSV format or long table markup.

That's why it seems good to move the table markup from the core Creole into CreoleAdditions and give the implementers and wiki admins more freedom in how they can treat the tables.