WPA3 delivers several security improvements. Here’s a big one:
When you connect to an open Wi-Fi network, the traffic between your device and the Wi-Fi access point will be encrypted, even though you didn’t enter a passphrase at the time of connection. This will make public, open Wi-Fi networks much more private.
You can read about the other improvements here:
What Is WPA3, and When Will I Get It On My Wi-Fi?
Unfortunately, WPA3 does have design flaws. See this site for more details:
Analysing WPA3’s Dragonfly Handshake
Also, WPA3 also suffers from implementation flaws, which can happen when a manufacturer writes the software that allows their hardware to use the new specification. You’ll need to check with each vendor to find security updates for specific devices.