Thanks for responses Meat With Dreams!
There is a bit of “have your cake and eat it too” Engineering resources are finite. As far as I can tell from poking around in the Substrate repo. Polkadot’s main focus right is prioritizing a system where many chains share the same security and availability model and thus get the arbitrary contract to contract call api. Cosmos’s main focus is hetergeneous security and object passing api. At the heat death of the universe, I would expect future blockchains to incorporate the best of both systems.
Fundamentally this is an article about worldview and priorities not constraints.
There is an idea that instant finality makes Tendermint slow. Tendermint has comfortable done 2-3 seconds blocktimes for months over 100+ independent validators on 3 continents. This is with a lot of low hanging fruit unpicked for performance optimization.
The benefit I can see for GRANDPA is that GRANPA will be live under conditions where Tendermint will halt. One of the biggest open questions that we answered this year for Tendermint is “will the network remain live with a group of strangers running validators all over the world?”. Testnets are an extreme test of this because there is minimal economic incentive to run a testnet. Our testnets haven’t experienced any problems with liveness.
An algorithm like GRANDPA might be more resistant to censorship attacks.
As I mentioned before, you either prioritize a compositional model that assumes all chains share security or one that doesn’t. I don’t think any ecosystem will really do both for ~5 years.