Both MCcoin purchases and withdrawals are always made from Bitcoins.
The purchase is always made in BTCs, but once it enters mind.capital, the value is in MCcoin, therefore, from that moment all the returns both for daily performance and for returns obtained by my referrals, are added to it. on your MCcoin account.
When you want to withdraw your obtained returns, from 50 MCcoin, these are withdrawn in Bitcoin at the official exchange you have at that time.
The same happens when you want to withdraw your capital after 90 days. The value of BTC, whether it rises or falls, does not affect your investment since it always works in MCcoin.