Is there anyway to use a woocommerce payment adapter to reload the fiat balance? For example, have it set for USD that users can deposit using paypal, or pesos they could deposit using MercadoPago. This way a user could select fiat using your adapter then deposit using any woocommerce payment plugin they selected.
No, the only way is to do a bank transfer, which you would have to then process manually.
The reason this is not implemented is that in practice it is not safe to do so. Keep in mind that credit cards are subject to chargebacks up to 30 days after the transaction, so if you sell cryptocurrencies (which are irreversible) with credit cards, you run a high risk of being a target for fraud. This is why not many sites offer this option.
The plugin is geared towards building exchange markets rather than “selling” tokens and other crypto.
Of course, you could still accept payments via some e-shop, then process the payments manually using the fiat coin adapter, but I would not recommend it for the reasons mentioned above.