Yes, absolutely. It’s like how to create extremely reliable software. Create a bulletproof micro kernel and then add layers. (Eg. QNX, sel4)
My understanding is that Liquid was intended to be used as you described. A “playground” where stuff like smart contracts and Monero-like confidential transactions were run but in a sidechain where it could experiment but not harm the core L1 network.
Perhaps these experimental features could either be added to Liquid or into a similar sidechain where you would peg-in and -out some sats into a network that looks like the core L1 but with experimental features.
I think it’s a great idea. 😀 The only issue I see is that people would probably want to experiment with it and wouldn’t use a large amount of bitcoin. With high L1 fees, the peg in and out transfers would be expensive on the base chain. Perhaps there is a way to do it to peg in and out with Lightning. 🤔