First things first, Aetherhub says this deck is illegal, but starting August 26 it will be legal, as Wizards releases Jumpstart: Historic Horizons on Arena.

Anyways, what could be more fun than turning something that isn't a creature into a creature just so that The Ozolith works with it?

... Well, we're only really doing a couple Planeswalkers here (for that), but some other cards here also happen to have counters on them and work with The Ozolith!

Replicating Ring is in the deck because the deck *can* go big on mana cost, with somewhat-expensive cards like Sarkhan, Search for Glory (into Chandra or Sarkhan), Castle Ardenvale, not to mention Workshop Assistant + Goblin Engineer can do some nice expensive things-- so there's often just going to be stuff you can do with most of the mana you have. Also, if it does end up replicating itself, now you have more things for the Goblin Engineer to sacrifice.

Crystalline Giant is in here because we need some early-ish creatures that we can defend with, plus stuff to search for with Goblin Engineer if we already have Ozolith, plus stuff to sacrifice to Goblin Engineer if we need a specific artifact in the graveyard back (sacrifice targets are also why Treasure Vault is in). Also, it's kind of the go-to card to put in with Ozolith, like they were probably designed with each other in mind.

Transmogrifying Wand is in because it's a good card, and we can sacrifice it and/or tutor it with Goblin Engineer (resets the number of charges on it)

Generally, the idea in this deck is, ideally you play The Ozolith, then Chandra, Fire Artisan, then Sarkhan the Masterless, then  use Heartfire your Sarkhan before combat, putting +6 loyalty on Chandra, swing with Chandra if it's safe, and then you can use her ultimate ability as soon as you have enough mana up for it to be worth doing. (The reason you'd use Heart of Kiran to do that here is because Sarkhan's ability isn't like most other planeswalker abilities; check out the rulings!)

Alternatively, you can +1 Chandra and when she turns back into a planeswalker on your opponent's turn, you can use Heart of Kiran to empty her loyalty at them like a machine gun (you're allowed to crew vehicles at any time, even if they're already creatures). I like to call this "Giving Chandra heartburn"

You could potentially just do 20 damage with those cards pretty fast.

Obviously that's not going to happen very often, but little parts of it definitely will!
- Any time you have Sarkhan and The Ozolith out, there's a good chance you can put a bunch of loyalty onto The Ozolith (though this is only useful when you get another Sarkhan later, unless you already have Chandra out).
- Any time you have Chandra and Heart of Kiran out, you can give her heartburn in reaction to your opponent trying something like "destroy target planeswalker" or just to cash in on her damage when your opponent isn't swinging at her and she's under 7 loyalty.
- Sarkhan isn't terrible with Heart of Kiran in general.
- Since Sarkhan makes creatures, it generally doesn't feel as bad to use Heartfire on them as it might if they were whole cards.

Also, it's not entirely even a question of whether you have the "combo" pieces available, it's more of a question of whether they survive. You can tutor anything you need (except Goblin Engineer) with Search for Glory, and you can get all sorts of useful things with Goblin Engineer, including two of the parts of what I feel I should actually call the ideal synergy situation.

I actually removed some copies of cards that I felt were super easy to get or not super necessary to have in the deck, in order to put a few random useful artifacts you might want to grab with Goblin Engineer.