Even a well-selling software product from a major company can sometimes be a black box because of inadequate, outdated, just wrong, or occasionally non-existent online documentation. The advantage of a programmer with much reverse-engineering experience is understanding things at lower levels. You will be a good hacker/burglar. You can work for other software vendors. Reverse engineering is good for understanding wonders that other programs can do. Sometimes it is helpful to have this skill to find bugs in programs for which you do not have source code and to fix them.