I'm starting with Beds24 and I asked them about their credit card processing tool and the answer I got was:
"Beds24 can collect payments for direct online bookings at the time of the booking. You also have the option to send payment requests go guests. Integrated payment gateways are Paypal (which also allows credit card payments), Stripe, Realex, Authorize.Net, asiapay, pesopay, siampay, paydollar, Paymill and Bitpay. To use this service you will need an account with the payment provider you want to use. There is a fee of €0.10 per transaction and the payment provider will charge their fees.
Realex supports also alterative payment methods to card payment. Check with Realex for the options for your country.
Alternatively Beds24 can securely collect credit card details. Cards can then be charged through your own bank or merchant account.
Some channels (Booking.com and Expedia) can send credit card details to Beds24. We have the option to send these directly to Stripe where you can then charge the card. To use this service you will need a Stripe account."
This means that anyway I need have an account with those merchants and that they're not able to collect payments directly, right? What do you know about those merchants?