Yeah I suppose it's just having the main Traveller source books together would be useful. I could see this book being really interesting to read but not if it means I have to buy a £50 box set to read it.
Same goes for Mercenary Book 1 - which has all the interesting stuff in about creating a Mercenary unit and fighting battles. Arguably the rest of the Mercenary boxed set books are just background stuff for this one book.
The Rift box has a similar book - Book 4 Deep Space Exploration Handbook. The rest of the box is just explaining the Rift worlds and history but this book is The book to read for deep space exploration. Shame its in an expensive boxed set.
Maybe you could release a set of just these books on their own ... or add them into a Referees Guide like D&D do - maybe a Traveller Companion 2!
Just an idea anyway.