The treasure was NOT his most valuable asset...
His most valuable asset was not the treasure, it was his friend. How rare is that? To have someone who is a loyal ally and partner for life not because they are being paid and not because they are afraid of you or being forced into it like a slave but because they feel indebted to you. This literary device comes way before Chewbacca. This man was to Edmond what Chewbacca was to Han Solo.
I loved the scene where he left the guy alone with the treasure for a few days while he went on an "errand". His friend could have stolen the entire thing and the only security he had was his trust in the man's loyalty.
That kind of loyalty is so rare that I think it is worth more than the treasure worth more than money. You can pay people to do things for you with money but no amount of money can pay for that level of loyalty.
Don't get me wrong lots of money is great too but I am wondering, if you could not have both and had to choose between a huge amount of money (maybe several million dollars) or an ally who is 100 percent loyal to you for life which would you pick? Personally I would pick the loyal friend.