I think the point is that it would be nice if people who are already paying for human-driven searches could also get an API key included in that plan.
Right now, API usage is only available using a PAYG credit system, even if you've already got a subscription. But giving subscription users an allotment of free credits that covers light API usage would be nice - I could plug it into my agent of choice for casual chats or exploration, while still having to buy credits for more extreme or production usage.
It would be nice indeed, but it's a bit like wanting to share a gym subscription when you're not using it. The economics would fall apart if everyone used 100% of their subscription, unless sharing was priced in from the beginning.