The IP address is like a temporary phone number. It could not pinpoint the person persistently but can be tracked down with the help of ISP.

Other information you can retrieve from IP address is geolocation information such as https://www.ip2location.com

It's not a phone number because it doesn't need to resolve back to anything in particular. With carrier grade nat for instance, it could be shared by many people. At best it's shared by a house.

With regards of tracking you with the help of the ISP, if you have someone with those resources, it's not you storing an IP address that's their biggest concern.

Geoinformation can also change daily. Figuring it out afterwards isn't reliable.

- You can identify trends and patterns in your traffic

- You can figure out where in the world your traffic is coming from

- It can be helpful in responding to security incidents

- arbitrary user, session and request IDs

- this can be done and then discard the address

- how so? What does knowing the address months later help? Something like fail2ban and other automated systems, sure, but long term logging?

If it doesn't have value, why storing it then?