Be careful if you're a user of cryptocurrencies. My goal is not to re-open a debate about them and their associated financial risks. No, I'm talking here about technical risk. Wallet addresses are long strings of characters that are pretty impossible to use manually. It means that you'll use your clipboard to copy/paste your wallets to perform payments. But some malware monitors your clipboard for "interesting data" (like wallet addresses) and tries to replace it with another one. If you perform a payment operation, it means that you will transfer some BTC or XMR to the wrong wallet, owned by the attacker.