People are complex, and they get energy in complex ways. Some managers get energy from writing some software. That’s great, particularly if you avoid writing software with strict dependencies. Some managers get energy from coaching others. That’s great. Some get energy from doing exploratory work. Others get energy from optimizing existing systems. That’s great, too. Some get energy from speaking at conferences. Great. Some get energy from cleaning up internal wiki’s. You get the idea: that’s great. All these things are great, not because managers should or shouldn’t program/speak at conferences/clean up wiki’s/etc, but because folks will accomplish more if you let them do some energizing work, even if that work itself isn’t very important.