Honestly that statement sounds like BS to me. Also, this person is trusting his life to a third party as well: the browser vendors’ cryptography implementation.
I think for an average person, the biggest factor is not the strength of the security. You’re already better than 99% of people if you use different passwords per site and store them behind a password. No hacker will spend weeks cracking your passwords if he can get the passwords of those other 99% for free.
So I’d say, pick the solution most convenient for you that is least likely to break over time. And an established name like 1Password sounds great for that.
PortableSecret is a complement, not a replacement.
e.g. where do you store the recovery key for your password manager?
I also use this to store tax documents and other mildly secret documents which definitely don't belong in a password manager that copies to who-knows-where-and-in-how-many-copies.
So out of curiosity, what password manager do you use? And as apparently you don’t trust your password manager, why do you use one? And how do you determine what is “useless” enough to be entrusted to that password manager you do not really trust?
I use multiple ones, they're kinda compartmentalized. One for web logins, one for critical operational secrets, one for 'cold storage'. Plus variants of PortableSecret for various other odds and end use cases like emergency recovery USB drives.
I trust everything I use to some degree. Otherwise I wouldn't use it in the first place. But the world is not black and white.
Just because I trust something enough to store secret X in it, doesn't mean I should automatically use it to store secret Y.
I think for an average person, the biggest factor is not the strength of the security. You’re already better than 99% of people if you use different passwords per site and store them behind a password. No hacker will spend weeks cracking your passwords if he can get the passwords of those other 99% for free.
So I’d say, pick the solution most convenient for you that is least likely to break over time. And an established name like 1Password sounds great for that.