This is how decentralized works on open-source coding, you can even follow the developer's progress which means the code itself can be checked by anyone who wanted to know the progress.  So there is more advantage to open-source than the close source wallet.  The reliability, security, and decentralization were open-source.

However, closed-source reduced the increase of imitators wallet or exchange but this isn't a problem if you know how to verify the legitimate one.