Ethereum didn't just shorten block times, it uses a variant of the GHOST algorithm, which as originally proposed for Bitcoin as a way to speed up blocks and increase throughput while maintaining good decentralization and security.

Thanks for understanding me. Unfortunately my original comment seems to have been massively downvoted by uninformed HN readers.

Sure, uncle blocks help increase the weight of the chain but are also wasted blobs of data forever taking up space on the blockchain. They serve no value other than to make the PoW weighting heavier.

How does block time affect centralization?

I understand that more storage is a centralization pressure, but how does blocktime relate assuming the same number of transactions?

Because mining is dependent on the rate at which information can propagate across the network. If a mining pool is able to hear about the next block 1s sooner than another pool, it has a significant advantage when blocks only take 12s to mine. If blocks take 10min to mine, that 1s is less of an advantage.

If miners get paid for valid blocks that don't end up included in the chain, that also makes the 1s less of an advantage. Hence GHOST. Here's the original paper [1] and a later one [2].

[1] https://www.semanticscholar.org/paper/Accelerating-Bitcoin-s...

[2] https://eprint.iacr.org/2016/545.pdf

Sure, maybe including uncle blocks can help secure the chain. It's not without cost, however: now you're forever persisting valueless blobs of data as part of your blockchain.

It's just an extra block header every few blocks, which is a minuscule amount of data compared to the transaction records. And it's not actually valueless since the uncles are part of the block selection algorithm and therefore contribute to security.