Using /usr/local is just fine. But I feel uneasy when a system directory is owned by just my user. What if there is another user on my system that also wants to

Using /usr/local is just fine. But I feel uneasy when a system directory is owned by just my user. What if there is another user on my system that also wants to perform a brew update? Using sudo would also be a security advantage since not every program running under your username would be able to modify all binaries in /usr/local.