Action 1: Prevent propagation of incorrect routing information
You see crazy things all the time. For example, bogen AS numbers in routes or Clearnet IP numbers in a route in dn42. It is important to be careful not to reinforce these errors yourself. Therefore it makes sense to filter them.
Action 2: Prevent traffic with spoofed source IP addresses
Action 3: Facilitate global operational communication and coordination
It is very important to specify a method of contacting someone. For example, I have contacted several people and a few hours later received an email from their provider that the email box was too full and the email was rejected because of that. Something like this is very annoying, especially when the networks are still active and in the worst case cause an error.
Action 4: Facilitate validation of routing information on a global scale
It's always interesting to see what others are doing. That's why I like to read other people's documentaries. Some have examples of how they implemented something. Sometimes I use them and adapt them for my needs.