Is zakat obligatory on cryptocurrencies purchased for storage and not for trading, with the possibility of selling them in the future?

Cryptocurrencies are digital currencies issued in the form of electronic data. If they gain general acceptance and trust as a medium of exchange, they are subject to the rulings of paper currency, meaning Zakat (definition) is obligatory on them and riba (interest) applies to them. Imam Malik stated that anything people accept as currency takes the ruling of gold and silver. Sheikh Abd al-Rahman al-Barrak views their use as permissible, stating that potential harms do not necessarily apply to all forms of transactions, and that they resemble certified checks. They are subject to the rulings of current currencies, like paper money. Therefore, Zakat is obligatory on them if they reach the nisab (definition) (minimum threshold) by themselves, or when combined with other currencies, gold, or silver. Their nisab is equivalent to 595 grams of silver.