Transformer recipe question

Good question. It's probably a resource cost issue, iron and gold is more valuable than copper and if the recipes where upped then people would start doing wonky stuff on servers to save on resources where the MV/HV transformers are MEANT to be used to save server CPU cycles.
But people still do wonky stuff with just LV transformers and bat boxes instead of upping their voltages to MV, HV and EV. They are soo greedy.

Or you can think of it like this:

Trnasformers work by wrapping large spools of copper wire around a drum, one large and one small. The difference in number of loops (and thickness of the copper) is what causes the voltage to be reduced/increased. Electromagnetism and all that. (how does it workz!?!?)
You CAN use copper cables to transport any voltage you want. Problem is the thickness of copper wire required to transfer large voltages. Big crazy transformers doesn't have copper wire, it has copper BEAMS (pretty much) for the extreme voltage size and then copper bars on the lower voltage side.

Open an old mobile charger and you will find a 240V-5V (110-120V for certain countries) transformer rated for ~400 mA. When you look at the copper wires you will see one THICK and one thin. The thick one is the 240V and the thin one is the 5V output.
It is the same story for larger transformers, only they are a lot bigger. Has a lot more copper in them and are bathing in a mineral oil to prevent us from having fun watching stuff burn.

Btw, while you are at it disassembling the mobile charger. Keep the transformer block from it. Hook up a 9V battery and a switch that alternates between the 5V two poles (there are two wires for each voltage)
Lead two wires from the high voltage side and ask someone to hold on to them while you rapidly flip the switch back and forth (simulating AC) and whoever is holding the other end should be getting some up to 480 volt jolts of electricity through his fingers.
This is perfectly safe btw, he will feel it but it cannot kill him. The amperage is way too low. (Otherwise you would have died from licking a 9 volt battery, which you clearly don't)

Have fun?!?

EDIT:

Oh, if you make the contraption i explained above... Don't leave your home with it in your pocket. If your country doesn't like people who wears tazer guns etc then you are going to be in a lot of trouble if they find it. It is EXACTLY how a tazer works but it has a small motor in it to flip the switch REALLY fast.

Can you please use meaningfull thread titles next time ?

As pointed out already, Transformers are special; both IRL and in game. They do things in special ways that unless you're interested in real electrical engineering you'd be completely TL;DR about.

As for the special cables, they are like switch boxes RL, and must be rated to handle the maximum load that can go through. Since that load is EV that's the kind of cable that it costs. (Where in a transformer the cable is used in other ways; there are other forces at work that provide the actual transfer in/out.)