What is the main benefit of decentralisation?

You are less prone to hacking - and it is not controlled by one company/building/place but rather many around the world.

And in most cases is much more transparent and there is much less room for manipulation, it is more healthy approach.

Many benefit to blockchain. But also customer need to buy ledger and make money secure.

What is ledger?

It is the safest and best wallet out there to store crypto.

And we will be able to store TCO on ledger?

If it's ERC20 then I think yes.

I serched the whitepaper but could not find any info on that.

We are building on Ethereum with ERC20.