[some_furry]

You mostly got it, yeah. Point 1, ECC is only also broken after Q-Day.

Hybrids obviously help if you believe Q-Day is far into the future, or never coming.

But if you take Q-Day happening as possible in our lifetime, the HNDL threat means data being encrypted today depends entirely on PQ security in the long run (since breaking EC with a Quantum Computer has an attack cost of like 2^30 or so instead of 2^120 or so).

[ls612]

So it seems like it comes down to a question of risk and cost. If your threat model is that it is much more costly for your communications to be decrypted today vs in 10 years then hybrid is a good strategy.