The level 60 henchmen came out before Waterworks and tower of the Helephant.
Now that those places are out, it would be nice if the henchmen loaded with the gear from those places instead of the weaker stuff from celestia.
Since they are one battle only, and cost 60 crowns, and can't be used in pvp, I can't see what problems it would cause to give them the better equipment and it would certainly make them a lot more useful in the higher level battles they tend to be bought for.