Is bank transfer currency fixed?

When selecting bank transfer, it tells you to use your accounts currency, which is Swiss Francs in my case. However, the SEPA standard requires a payment to be in Euro.
Non-Sepa payments come with high fees (18€ in my case), so I wonder wheter T212 cares about the currency or just does auto conversion with their (good) FX rate. Depending of the amount of course, but I guess exchanging CHF -> Euro -> CHF is still better than 18€ of fees

If you transfer funds in EUR, and then we have to add those to your CHF account > we’ll use the current exchange rate.

Scenario 2: if you deposit in EUR towards our CHF bank account > then the conversion is applied by your bank.

I am mainly concerned about transferring from my bank to your (T212) account, that’s what you mean with scenario 2, right?

But my bank shouldn’t even know your bank account’s currency and SEPA is always in Euro?
I imagine if anyone, then your bank (Barclays) would auto-convert it to T212’s account currency.