when I saw the last update about "New Stoneheart Battleground Mechanics" I start to think about the purpose of it, and I couldn't find a good answer so here I am: 

I have this stonehead castle, but I can't produce or get soulstones!! What the developers are thinking, maybe I didn't understand the "mechanics" of it.

When I attack/defend a stonehead battleground I don't receive troops, so If I got it right, I can't produce soulstones and I can't receive it either?

I still don't understand why they create another castle for this stonehead because for me this castle is just to produce adamantine (as all the other resources cost too much for too little), why they didn't create these new adamantine buildings and enable it to put in the same caste? 

the new update is enabling to put these stonehead units into the catacombs, this is another point I didn't get, when I attack a stonehead castle all the units will be in the catacombs?

Ok maybe I am doing really stupid questions here, but for me, these stonehead castle and buildings are useless.

They did something similar when they added the Vampire Units

They could only be built using Maranian Amulets

but that did not increase plarium profits

so they dreamt up Stonehenge Loft Conversion

The only purpose of this was to introduce the new units, which are pretty much too expensive to produce without resorting to coining (and far too slow to build an army)

Hello!

Sir Dan is right regarding Soulstones and their increase in the Tournament's Rewards.

As for the reason why it was added. Actually, both of the reasons Sir Dan mentioned are correct:

1. Of course, we wanted to add the new content that will allow even very experienced players to find smth new in the game.

2. I won't deny that from the business point of view (yes, we run the business here), devs added smth that will bring profit to the company as well.

Without it, we won't be able to run the games at all.