Unfortunately, Steel Grave at the moment is merely a place to farm MK blueprints and a source of very modest BP gains. You can complete all 15 episodes rather easily and you soon lose interest in what could have been good repeatable content.
The concept of Steel Grave itself is interesting (or it would be if it was actually a challenge after you reach 55) but it can easily be improved or enhanced not only by adding more episodes with higher difficulty and better rewards, but also by adding some features like the following:
-Make a "custom" episode where you can list the enemies you want to fight against: For example I want to fight 3 bosses at once, and I want to choose which ones. This would not only create many possibilities and repeatable content but also raise the difficulty and incentivize players to improve their skills and gear.
-Add a "training dummy" inside Steel Grave. It should have infinite HP and would allow players to spend time practicing their combos, testing their gear, akashas and different setups. This would also be great for new players who are still familiarizing themselves with new skills. It would allow everyone to test their dps by taking time to look at the combat logs since there would not be the need to worry about getting hit or dodging enemies' attacks.
I think the implementation of any of these 2 modes should be fairly easy in terms of the dev work involved, and it would give a lot of value to an otherwise rather irrelevant instance.
Thank you for reading.