Well, I don't think it's quite "nothing". Newer phones don't have access to checkm8, and getting a private jailbreak or exploit working can be non-trivial. And in some cases, researchers may need to avoid reporting that exploit to Apple in order to keep using it.
It's a good step. It's just not sufficient, especially given all the other restrictions.
And this will continue to happen until Apple just starts selling the damn things to anyone who wants them, instead of trying to gatekeep them to people who are playing by their ridiculous security disclosure rules.
Sure, some crazy people who aren't security researchers will probably buy them too and use them as daily drivers (I'd probably be one of them). So what? I don't understand why Apple feels the need to hold this stuff so close to their chest. Everyone in this scenario knows exactly what they're buying.
Oh, that's a shame. The slide in the referenced tweet says, "advanced debug capabilities", so I'd assumed that's what it meant. I wonder what else that could mean?
No sources or structure layout or symbols, so you're still stuck waddling through megabytes of compiled code to reverse-engineer everything from scratch.
It's Apple drumming up absolutely nothing, and from my point of view it's mostly a PR stunt.