Quais são os problemas da carteira de Bitcoin?

In the realm of cryptocurrency and finance, one of the most frequently asked questions revolves around the challenges of Bitcoin wallets. Could you elaborate on some of the key issues that Bitcoin wallet users often encounter? For instance, are there any security vulnerabilities that pose a risk to users' funds? Are there any scalability concerns that limit the wallet's capacity or transaction speed? Furthermore, are there any user-friendliness concerns, such as complex interfaces or lack of customer support, that hinder adoption? Addressing these queries would provide valuable insights into the current landscape of Bitcoin wallets and their potential areas for improvement.