Why nobody in the yachting industry accepts credit/debit cards, PayPal, Zelle or other cash apps

Quite simple – Fraud.
The amounts moved around are significant. That’s why we (and everyone else) needs to be sure that once the money arrives, it can’t be pulled back.
You’d think that with credit/debit cards that would not be the case, right? Nope, the bank freezes the money on our account and reverse them to the sender (months after the card payment!). So guests can come back from the vacation and just get their money back. Then we get to sue them, which is not how we want to spend our time. There is plenty of stories online, like this one.
PayPal has issues with the big amounts and frequently freezes accounts for “security checks.” For weeks/months, crippling businesses in the process, more here and elsewhere.
Another issue is credit card fraud. The client books a charter (from a stolen card), then cancels and asks for the money to be returned to another account. If we start advertising credit/debit card payments, these people will start swarming like vultures.
There are dozens of stories. First hand, other brokers stories…
The bottom line is that we do accept bank transfers only. We’ll gladly explain to you why that is, share the experience. If a client tells us he/she will pay only with a credit card, we’ll consider that client a potential fraud case. Same goes for you. If a company asks you to pay with a credit card, please check them thoroughly. There are sad cases where non-existent companies “book” the charter and when the guests turn up…
Please do understand us. We want your business, but we’re not going to risk losing our livelihood to get it.
Hope that makes sense!