In the case of Bitcoin simple actually doesn’t mean more secure (since bitcoin forks constantly).
Simple protocols take time to land, and are often digestions of much more complicated protocols. We’ve seen that with TLS being simplified into Noise, or the sponge function for hash functions. If you look at the history of consensus protocols they are getting simpler and simpler as well, arguably hotstuff and streamlet and all the hotstuff variants are simpler and simpler to understand.
Simple protocols take time to land, and are often digestions of much more complicated protocols. We’ve seen that with TLS being simplified into Noise, or the sponge function for hash functions. If you look at the history of consensus protocols they are getting simpler and simpler as well, arguably hotstuff and streamlet and all the hotstuff variants are simpler and simpler to understand.