Yes. Accommodation payment via FlatClub is 100% secure and all payments should be made on the FlatClub platform. Your card information is never stored and the payment you make to complete a booking is safely held by FlatClub until you check-in.
When payment is kept on the platform, FlatClub offers 100% guest protection against frauds and scams and the ability to enforce cancellation policy protections.
FlatClub does not process security deposits. If a host requires a security deposit it should be paid on arrival, never before. An exception to this rule may be made if deposit payment is being made directly into a government regulated scheme like the UK's Tenancy Deposit Scheme.