SRX-Difference Between static route and traffic-selector.

Hi,

i would like to understand the difference between apply traffic selector in a vpn or apply a static route using the st0.x associated with security vpn.

Scenario:

source: 10.10.10.0/24

destination: 10.20.20.0/24

Follow the two statement to reach the configuration:

Traffic selector config:

set security ipsec vpn VPN-10 traffic-selector NET-10 local-ip 10.10.10.0/24

set security ipsec vpn VPN-10 traffic-selector NET-10 local-ip 10.20.20.0/24

Static route:

set routing-options static route 10.20.20.0/24 next-hop st0.10

Both configuration is working to me, but, i would like to understand the difference between both way to deploy.

Tks,

Joao Victor