You can't have monero functionality while also being able to verify coin supply. Monero sidechain will have zero benefit to users over monero shitcoin and 100% benefit to miners.

Sidechains as scaling solutions is also useless. People can already benefit from working L2s without them being linked to miner revenue. Again a "use case" which only benefits the miners.

DCs will only boost miner revenues with zero to negative value for the rest of the network. Therefore it's easy to discern who is funding the hype around those BIPs.