Yeah but you can look up the name "Rugal Pa'Dar" and get the information from Memory Alpha/Beta. Even if there isn't a specific article for the exact name/subject, it will usually give you search results where you can find that information.
What I'm saying is that's not all the annotations are about, though. For instance, no wiki article would have this, from the Summon the Thunder annotations:
The notion of “the Vault” is something we came up with for this book. Our thinking was that, given the security surrounding Vanguard’s true mission, there would have to be a place within the station — off-limits and in fact unknown to the vast majority of Starbase 47’s crew — where Xiong and others briefed into the project could work. The Vault’s also intended to be a repository of artifacts and other pertinent items and information discovered in the Taurus Reach and with a link to the “mystery.” Consider this Vanguard’s equivalent to APO (Authorized Personnel Only) from the Alias television series.
And if Dr. Gek reminds you of a Tellarite version of Marshall Flinkman … well, go with that feeling.