The most important advantage of Ethereum 2.0 is its scalability. Ethereum 2.0 will have shard chains due to which it can conduct up to 10,000 transactions per second whereas Ethereum can support only 30 transactions per second.
This also leads to a lot of delays and network congestion which will not be the case in Ethereum 2.0. The implementation of shard chains speeds up the network and can scale more easily as the transactions are handled in parallel chains instead of consecutive ones.
The main idea behind devising an upgrade to the existing Ethereum is to exercise more safety in the entire transaction. Many proof of stake networks has a very small set of validators. This accounts for decreased network security.
Ethereum 2.0 requires a large set of validators, approximately 16,384, which makes it more decentralized, secure, and less prone to manipulation.