Content Blocking Extensions are pretty neat from a privacy perspective, but they're quite limited in functionality since they're basically glorified block lists (why you'd pay $2 for a list that's freely published is another question) and it requires support from the platform. uBlock supports a lot of features that CBE apps can't.
uBlock origin has a lot of features beyond being a simple ad domain blacklist. You can remove elements from websites at wish. It can spoof information about which fonts you have installed to websites, block WebRTC and more. A pure ad blocker with a smaller feature scope will require fewer permissions. While I have not read the source code my self I have a hard time believing that uBlock origin is not limited to the lowest amount possible of required permissions to do the job it does.
Not blockers for Safari like Wipr that use Content Blocking Extensions: https://giorgiocalderolla.com/wipr.html