Why are people so optimistic about Ethereum rollups solving issues?

I see so many posts across different subreddits saying that rollups are going to solve network gas fees.

What am I missing? It seems really impractical for end users to use rollups for this purpose.

• ZK rollups are processor-intensive, so they're gas expensive and don't solve gas fee issues.
• Optimistic rollups settle in a week. That's way too long to be of practical use for most cases. I can pay someone to settle faster, but that defeats the purpose of reducing gas fees.

What are the main use cases?