Perhaps, but the add-ons are incredibly easy to use and flexible based on user needs. Need colors for your bookmarks? What about inspirational slogans or funny pictures? Want to use your font increasing plugin on a different book or even a non-book item like your food packaging or crafts? All easily done. You don't need to get your add-ons or books from a single, central repository.

Finally, though search is lacking, users have developed some clever ways to overcome that issue over time including indexing and tables of contents.