Route based vs Policy based VPNS
Most firewalls support both policy based and route based VPN’s. Which one we are supposed to use in most cases doesn't really matter, but there are a couple of things to consider.
Route based VPN is more flexible, more powerful and recommended over policy based. However a policy based VPN is usually simpler to create.
A route based VPN creates a virtual IPSec interface, and whatever traffic hits that interface is encrypted and decrypted according to the phase 1 and phase 2 IPSec settings.
In policy based VPN the tunnel is specified within the policy itself with an action of "IPSec". Also for policy based VPN only one policy is required. A route based VPN is created with two policies, one for inbound and another for outbound with a normal "Accept" action.
A static route is also required for a route based VPN, so anything destined to the remote network must go through the virtual IPSec interface which was created when specifying this within the Phase 1 settings.
A route based VPN is also required when using redundant VPN connection. A route based VPN only works in route mode, where policy based VPN works in both route and transparent mode.
If your requirement is to create redundant VPN connections and your firewall is in route\NAT mode (99% of the time it is) then use a route based VPN. If you don’t require redundant VPN connections then you can use a policy based VPN. There are other reasons to use one or the other as well but they are rarely required.