I use a private window for banking/paypal , I don't trust the extensions or the other tabs so for this cases I get more security.
You're here bullshitting that he needs "true security" like he's dealing with APTs trying to access his bank account. He's not. He's concerned about other tabs + addons, and private browsing mode is a solution with the slightest friction for his threat model.
Please, in the future, try making security assessments based on the actual threat model.
EDIT: "threat" instead of "thread".