You are free, and no one is against you changing your password because, as you indicated, it is for security reasons.
But what reason would that be that you resort to changing passwords? I mean, you can just tick the Always Logged In in your browser so you don't have to relog. I don't know of any reason that someone will hack your forum account even if it makes a lot of money from signature campaigns, you can always report that you're account's stolen.
You should know how to properly protect your account, and one way is by changing your password regularly and backup securely.
Storing your password online (eg at Google) is too risky for your security. It is not recommended for anyone concerned with security and privacy although you can login easily without bothering.
Imagine if you never backup your password, but you saved them in your browser, but suddenly you lost your device or it broke for something, how can you recover your account?