[ckozlowski]

There's a few cases; some have mentioned scenarios where you might want SSL offload. Those are perfectly valid. I'll contribute another.

Let's say you have a single web server you need to have up all of the time. You need high availability, but not necessarily instant fail-over, because you want to keep your costs low, and so you don't want two instances running all of the time. It may not serve much traffic at all, so there isn't much load to spread. What you can do is place an ELB in front of the web server, set a condition to start a new instance if the page becomes non-responsive (i.e., a failure), and set the auto-scaling to "min 1, max 1." This way, you'll always have a pool of one server, that will automatically rebuild if the instance fails.

I admit, it's not a common use case, but it's one of the more clever uses of the ELB I've heard. =)

[Xorlev]

We do this. We have 50+ ASGs for the same reason. Often it's min=3, max=3 for HA, but if a machine fails it's automatically replaced.

Every service in our infrastructure runs the same way. Some have scaling policies, some don't.

DBs like Cassandra are also in ASGs since if one of them terminates and new one can come up and bootstrap without operator intervention.