The reasons to use IKEv2 are pretty straightforward:
It’s a VPN protocol deemed very secure and supports modern encryption.
It’s great for mobile users (road warriors) through its Mobility and Multihoming Protocol (MOBIKE) support, making the protocol resilient to network changes.
As mentioned above, it’s also natively supported by most operating systems today, so you can use IKEv2 without requiring a dedicated app from your VPN provider.