Prizes as interest aren't uncommon or scammy in themselves. My bank used to have a savings account like that https://www.westpac.co.nz/accounts-cards/savings-accounts/sa... . I inherited a UK government bond from my dad that had cost 1 pound many decades ago and would go into an annual prize draw. Turned out it never won a prize and the bank/government sent a cheque for 1 pound.