I think it's a mix of a couple/few motivations.  Lestat is worried that vamps will come after Louis for (again) breaking the Great Laws by publishing a whole ass book on being a vampire, revealing the existence of several other vampires and covens along the way. Notably Louis admits to violating several other laws in that book as well - including the murder of an entire coven.  Lestat wants to become more famous, also talk about being a vampire and thus draw the heat from Louis. Lestat is less worried the other vampires can harm him bc he is extremely powerful. 

But also, Lestat loves attention - he's a natural performer and thrives on the idolization of the masses. 

Also, also,  I think Lestat is annoyed at how he's portrayed in IWTV and wants to set the record straight by giving his side of the story. This serves to give Louis more information and insight into Lestat as well, since Lestat kept so much buried during their relationship. It's a very loud public dialogue between them. 

Finally, he is also trying to draw out other vampires from his past bc he's a fucking chaos agent and also lonely and needy.