Quite so, quite so... though it does hinge upon whether one wants "real-world" information about the genesis of the character, how the movies were made, etc. For that purpose, The Complete Making of Indiana Jones is probably the single most essential volume in an Indy fan's library (even if it's not so "complete" as to include much in the way of stuff on the TV show, for example, or the reception of the fourth movie).
For "in-universe" information like character biographies and so on, though, it's an open question...