Every park is different. Visiting Tokyo is a great idea. Admission is quite cheap. The biggest difference is they’re a cash economy so credit cards can’t be used. A tourist can’t reserve the famous Tokyo Disneyland restaurants using an American credit card since it cannot be accepted there. Wait in line. Upon arrival at hotel, pay for all reserved rooms in advance with Japanese yen. That’s why I brought $2000 worth of yen to pay for everything once I’m there. Buy all tickets at home if you can. That’ll save you from having to bring more cash.
What are you talking about??? Credit cards have been accepted at the parks for well over 20 years in Tokyo. You must not have been paying attention. Most hotels (chain hotels and Disney hotels in the city and nearby the park) have taken credit cards since they opened. While it's true, they're more cash focused as a society, certain segments of businesses have to cater to leisure and business travelers, and that requires accepting credit cards.