Signal developer here. It's just because notification reliability is always a top support complaint, and a lot of people turn off notifications and don't realize they've done so. Admittedly, once a month is likely too aggressive.

> why does it keep asking?

Why does any software keep asking you to do things you explicitly told them you don't want to do? Because it's in the software developer's best interest to get you to do them, not yours. We've gotten way past the point in software where we no longer expect the software to serve the user's interest and solve the user's problems. Now, the expectation is that the user gets nagged and coerced into serving the software's interest and solving the developers' problems.

EDIT: Looks like a developer confirmed this in a sibling comment already: It nags you because that solves their support problem.

Messaging platforms where people receive and promptly respond to messages are more successful in the long run. That's why SMS overtook email. If you own a messaging platform there isn't anything inherently nefarious about pushing people to enable notifications.

Pretty sure that's just iOS behavior + app design. If notifications are off, apps will occasionally prompt again to make sure you didn't disable them by accident or miss something

Reminds me what Whatsapp if you set up a 2FA PIN, which forces you to type it about every week to check if you forgot it. So annoying.

NSL, perhaps?