Seems logical to me. They are saying that the transfer time depends on which currency, from which country's bank you use to fund your Wise account.
I have found it better to 'stock up' your THB balance as and when the exchange rate is good, like when GBP = 47 ! Then do a THB to THB transfer when you need/want the money to be in Thailand. Usually instant unless you need it to be International. Then it takes a day longer, as mine just did.