No downsides if you think every transaction should be a Bitcoin transaction. Cryptoeconomics is required reading for this topic.
https://github.com/libbitcoin/libbitcoin-system/wiki/Cryptoeconomics
Discussion
Thank you for sharing. I promise to read it🫡
What are your thoughts on Drivechain?
I haven't even read the bip300/301, but basically I don't like any idea of blockchain except for Bitcoin.
IMO, blockchains can't be the solutions for Bitcoin scalability.
On the other hand, LN is one of the L2 solutions, because LN allows low fee payments without using any other blockchains. I also believe that Ark is one of the candidates for solutuons. (I don't know CTV, Ark well, yet)