You want to build a stable system. Set it up so that the lower level pieces work and will continue working if untouched so you don't have to think about them and instead focus on the higher level stuff.

A software that is subscription based means your computer system seen as a whole will stop working at some point in the future if you don't remember to take a specific action (like updating the payment method or some such). It means uncertainty, it basically means you can only guarantee your system will work as-is for the next month. The more software of this kind you have, the more complex your system becomes to maintain in a given state and it burdens your mind.

I think it's fine for software you only intend to use for a few weeks/months at a time, or for software where you always want to be on the bleeding edge of tech, but for things as low level as a password manager? You want something really stable. It should also not update itself. So if we are not interested in updates what's the point of paying monthly?