Websites need to ask for consent before sending system notifications via the Notifications API. If a user declines, that website is blocked from asking again (for obvious reasons)
But many websites cheat this by showing a fake consent popup designed to mimic what the browser would show. If a user clicks "Decline" on the fake popup, the website won't show the real one to avoid being blocked. So the next time you visit the site, they'll be able to show you that popup again as many times as they want.
If a user finally clicks "Accept" on the fake popup (out of frustration probably) then they'll show the real popup. To most people, seeing two popups might seem like a glitch, and will just mindlessly click "Accept" twice.
The only way to circumvent this is to click "Accept" on the fake popup, and then click "Decline" on the real one. 99% of people aren't going to know how to do that.
...I'd post this myself as a comment, but I don't like that it's asking for so much personal information (full name, email, state, city, phone, etc)