I consider the contextual and intertextual discourse provided by Tolkien to be profoundly important when considering reading the actual story. The layers of addenda Tolkien provided both increases the understanding of the text, expands the mythos, and certainly aligns one in the direction the author wished for one to read his work. This, in my estimation, is not a bad thing.
One only has to go back to the 2nd-edition forward of LoTR, where Tolkien (in his usual curmudgeonly manner) dismisses the attempts by some critics and readers to apply the modern modus operandi of nuclear war to the tale and comparing characters in the book to infamous figures of WWII. Readers will find a host of implications not pertinent to the text - it is the foundational tenet of fan-fiction writing.
Of course, as
Zigűr referenced, one must be cautious when delving, because one might unearth a sleeping Balrog (with wings). Tolkien can be deceptively vague, meandering, hypocritical, annoyingly duplicitous and even forgetful, but given the hours upon hours of stimulating reading provided by the external commentary, and particularly C. Tolkien's posthumous distillation of his father's papers and unpublished works in The Silmarillion and the HoMe series, I think, for myself, it only adds to the immersive process.