It is when compared to Firefox. Safari and now Google claim that it's for security, as the newer interfaces expose way less attack surface for malicious add-ons. I think that it's true that it does improve security, although I'm not sure that I believe Google when they say they're not doing it to stop people from blocking their main revenue source.

At least the blocker I use, uBlock Lite, isn't nerfed. It doesn't have Manifest v3-ish limitations, and can do dynamic blocking, injection, etc.