I'm answering the specific points made about FastMail with the whether they are correct or not.
We don't have an account with a US bank, though we do have an account in USD, and we're an Australian company, not a US company.
Other than that, our main datacentre is in the USA, and obviously if every US bank decided not to allow transactions to our accounts, we would be in trouble. That would be true regardless of whether we billed in USD or AUD.
Same here, I think Fastmail should definitely consider hosting their servers in various locations and allow their customers to choose where they want their primary storage to be.
We don't have an account with a US bank, though we do have an account in USD, and we're an Australian company, not a US company.
Other than that, our main datacentre is in the USA, and obviously if every US bank decided not to allow transactions to our accounts, we would be in trouble. That would be true regardless of whether we billed in USD or AUD.