I've had an extra-usage quota for months now. They even gave people free credits for that some time ago.
It's useful once in a while when you're like 90% done, run out of usage and the next refresh is hours away. Then you can push that feature to completion and swap to another model that's not on cooldown.
> Model access: When using a Pro plan with Claude Code, you will only be able to use Opus models after enabling and purchasing extra usage.
And your extremely slow loading archive link is just the same page with the same text.