To me as self loading freight it does all seem rather odd.
The whole point of regulations such as the Technical Instructions for the Safe Transport of Dangerous Goods by Air is to control circumstances not under the full control of, in this case, the pilots and airline, and also the crew and customers on passenger flights.
Regulations get drawn up in the light of worldwide experience of what can go wrong. In the case of rechargable lithiums consensus appears to have been reached that they don't go bang often enough to justify an outright ban. So far there have been comparatively few problems. Billions of rechargable lithium batteries have been made, not very many social media pics.
This is where I start getting worried.
Battery technology is forever changing. Placing every single rechargable 'lithium' battery into a single category and pronouncing on whether they can be air freighted in the hold or not is too broad brushed. Furthermore, if a single manufacturer cocks up either in design or manufacture of just one single battery, the first time we'll hear about it is in the accident investigation report.
It's also a bit odd given that there have been cases where passenger-carried batteries have let go in flight. There is precedent for them failing...
So that's my concern. The ICAO consensus is founded upon everyone else's standards of quality control and testing and their adherence to them. So far as I'm aware the aviation industry has no control or visibility of those standards, yet safe aircraft operation carrying a cargo of batteries is dependent on them.
The regulations could require a thorough inspection of the paperwork (test results for the design and batch, manufacturer background check, etc). That would go quite a long way towards knowing whether a cargo is likely to be problematic. Anyone know whether such a paperwork regime is on the table? Afterall, an aircraft wouldn't be allowed to carry explosives unless an awful lot about the sender, recipient, manufacturer, etc. was known in advance (though of course that is a hypothetical situation, but not so far removed from carrying tens of kilos of highly fraught lithium...).
Otherwise it seems that literally anyone could place a cargo labelled "rechargable lithium batteries", and it would be accepted.