Uses for separate root and home partitions

I'm just curious to hear why people use separated root and home partitions, or don't use that.

For me, I'm tempted to use separate partitions so that I can keep my base installation as simple as possible in root, and then install everything else to home. That way I can easily revert to a fairly fresh install, or access my home partition from other distros if I want to try them out.

Does anyone else have use cases for using or not using separate partitions?