Subscription

[Hiruki]

Cheaper in what way? Because there's never been a moment in history that BRL had more value than USD. If what you meant is that there was a time that Mogstation payment, converting BRL to USD, was cheaper, yes, that's is true, that'd be around 4 years ago if I remember correctly, but Steam players always had the option to pay both ways: using Steam Wallet, therefore Steam regional subscription, or via Mogstation.
Yes, Steam subscriptional would be a bit more expensive but you can get money on Steam through their marketboard, selling Valve items and stuff, so, even nowadays, you can play FF via Steam without even putting IRL money sometimes.

I don't remember exactly the details about this SE offer so I won't argue about it, better than saying wrong stuff.

I'm from Argentina, with the new tax from the government I paid my basic sub 16.99USD instead 12.99USD.
I'd love to have the option to link my acc with my steam acc. Could you paid the sub cheaper if you use Steam? Like, can I pay the sub in ARS?

[yTony]

I'm from Argentina, with the new tax from the government I paid my basic sub 16.99USD instead 12.99USD.
I'd love to have the option to link my acc with my steam acc. Could you paid the sub cheaper if you use Steam? Like, can I pay the sub in ARS?

The people who bought their games on Steam have an option to link their accounts and pay using Steams price table. So yes, you'd be able to pay with ARS and probably a much cheaper subscription.