1) Iteration: We get to practice our stuff on real entities (language, OS, databases, etc). Do architects get to "practice" actual work at their home? Do new doctors get to try experimental surgeries? Do amateur civil engineers get to build those iconic bridges? They can do computer simulation ... but it is actually a software.
2) Hackathon: Can't imagine this happening in say medical field, mechanical engineering, law etc. Software Industry is one of few industries where this can be done.
3) Changing the world quietly: Many in my relatives are not programmers. It is hard to explain to them in what ways software is changing the world.
4) Open source: Imagine Coca Cola sharing its secret recipe. It won't but we as SE get to learn from open source projects. Now there is a cultural aspect to this but the point is that we as SE can experience it more than other professions.