Since zk rollups are so computationally intensive, it is nearly impossible to recreate the full EVM environment that layer 1 and Optimistic rollups are able to run. Therefore, this scaling solution is confined to single types of transactions and cannot host a wide variety of projects on a single network. However, since zk rollups compute and verify transactions on their own, the technology is able to offer fast finality and transaction costs that are significantly lower than Optimistic rollups and magnitudes lower than mainnet.
Source: https://www.coindesk.com/layer2/2022/02/16/ethereums-rollups-arent-all-built-the-same/?utm_medium=referral&utm_source=rss&utm_campaign=headlines