If the contract doesn't specify specific payment methods then then legal tender laws means the landlord must accept cash as payment. (law.stackexchange.com)
In most countries, legal - tender laws specify what currency citizens and businesses are obligated to accept for the settlement of debts. (digitalcurrencycouncil.com)
There may be legal tender laws, but I can tell you that there would be fights over things like this. (alephblog.com)