Binance card fiat conversion?

I have a question that I can't appear to discover a direct reply for. Principally I want to understand how binance calculates the conversation of fiat for their card.

I do know the card is denominated in euros so no matter is in your funding pockets is converted to euros. So for example BTC has a Euro pair on binance, so no matter Btc you might have it's price towards the euro is chosen... But where it gets difficult is firstly when the coin doesn't have a euro pair.

My first guess is, because every coin has a usdt pair and there is a Eur/usdt pair, that coins value might be first denominated in Usdt then transformed to euro to provide it a worth.

So my question, is that this the identical with fiat? Does binance convert the overseas foreign money (fiat) into euro using the actual visa/financial institution fee or does binance first convert the fiat into their usdt price then give its relative value as usdt to euro?