Also potentially useful if you're involved in any way in policy formation. (And yes, even when there are political constraints).
In practice, I find the most useful aspects of having a working knowledge of lots of different ethical systems is that it makes it easier to:
(a) quickly drill down to the core of many disagreements. Even if they're not resolvable, being able to find them quickly often saves a lot of pointless going around in circles. (There are network externalities involved here as well. Knowing this stuff is more valuable when other people know it too.)
(b) quickly notice (or suspect) when apparently sensible goal sets are incompatible (though this is perhaps more to do with knowing various impossibility theorems than knowing different ethical systems).
I've often had half-finished LW post ideas and crossed them off for a number of reasons, mostly they were too rough or undeveloped and I didn't feel expert enough. Other people might worry their post would be judged harshly, or feel overwhelmed, or worried about topicality, or they just want some community input before adding it.
So: this is a special sort of open thread. Please post your unfinished ideas and sketches for LW posts here as comments, if you would like constructive critique, assistance and checking from people with more expertise, etc. Just pile them in without worrying too much. Ideas can be as short as a single sentence or as long as a finished post. Both subject and presentation are on topic in replies. Bad ideas should be mined for whatever good can be found in them. Good ideas should be poked with challenges to make them stronger. No being nasty!