You wouldn't have to worry about an enderchest, you do about a normal chest or in this case a shulker box. For example in overpowered mode this could be very usefull, you have lets say 5 armor sets in you inventory, and a shulker box, with another 5 sets, that would add up to 10 sets in one inventory, plus a shulker box is easy to break ;)If you constantly protect it, than there will be pretty much no use to it as you will waste your game time trying to get it back wherever you left it. Anyone can steal the items you have in there, that's why with an enter chest it would be much more efficient.