Sidechains lose a lot of the benefits of being on-chain and are a ton of work to implement.
Yes, Twitter volume + all other apps (Uber, etc) would 10's to 100's of PBs per year.
I don't disagree we may need to go off-chain eventually. But I think it's good to explore how far we can go on-chain before engineering other solutions.
Absolutely. When/if onchain images are too expensive, offer an option to save them, insecurely, with no guarantees, offchain.
