What is the difference between the two methods to create static routes?

There are two methods to create static routes:

The ip route 10.1.1.1 255.255.255.0 eth 0/0command generates an ARP broadcast that looks for the next-hop IP address.

The ip route 10.1.1.1 255.255.255.0 172.16.1.1command does not generate an ARP request. It keeps Layer 2 out of the routing process.