From Europe. Genuinely never used anything other than the card provided by the bank. But there are some nefarious companies which require a SEPA mandate for recurring deductions and make it hard to cancel. I also have my reservations about always using a card directly linked to my bank account but so far so good.
Yeah, it can get problematic. I got into some infinite loop of a plane ticket system one day. They charged me around £800 per iteration continuously until the charges got rejected.
It got reverted within a day or so, but having your current account wiped without knowing when will it get resolved and whether any money you put back there will disappear as well is not a great situation to be in. Having at least two different accounts in that case is good.
