Bridging to/from L1/L2 (Optimism Standard Bridging vs. 3rd Party Bridging)?

I was reading some documentation on the Ethereum.org website on how the Optimism Standard Bridge works (at a high-level, not a developer, just a retail person).

From what I got out of the article is that the standard bridge is a "simple" mint/burn procedure i.e., lock up ETH on L1 and then mint the same amount of ETH on L2, vice/versa.

It takes 7-days for L2 to bridge back to L1 using the standard bridge (challenge period)?

At the end of the article, and from observing on the bridging link, there are third party bridges that enable faster withdrawal from L2 back to mainnet. Does this work because people are depositing/staking their own assets and are creating some sort of liquidity pools? Are these 3rd party bridges as safe as the standard bridge, or are they more centralised and not trustless because it requires people to deposit assets into contracts?

Why would one want to use the standard bridge with the 7-day lock-up? What prevents most people from using the third-party bridge other than liquidity issues (assuming that my liquidity pooling theory is correct?

Are all of the 3rd party bridges from Optimism to mainnet safe to use, or should one wait for audits? There seem to be many 3rd party bridges.

For people who provide liquidity to 3rd party bridges, is it possible for them to get rugged by the developers?

Also, is it possible for Ethereum to implement State Proofs (from Algorand) to help secure bridging to L2s, or is that mainly cross-chain