"They get created and destroyed fairly frequently, and change public IP addresses as a result."
That's half the story. A load balancer (static IP) will often offload the traffic to another IP. Dns is not doing much for you here.
Furthermore, DNS often has a significant lag time between changes - switchovers usually measure in days, relying on dns to cover your routing is usually only pratical with a custom dns resolver anyways.
Even in the case of websites with truly dynamic access like this, then, it's enough to run a targeted query from your local resolver - an argument for local resolvers over your custom-roll-a-script solution...
That's half the story. A load balancer (static IP) will often offload the traffic to another IP. Dns is not doing much for you here.
Furthermore, DNS often has a significant lag time between changes - switchovers usually measure in days, relying on dns to cover your routing is usually only pratical with a custom dns resolver anyways.
Even in the case of websites with truly dynamic access like this, then, it's enough to run a targeted query from your local resolver - an argument for local resolvers over your custom-roll-a-script solution...