The "why" should become clear from the bug description. Obviously it is important in the commit message but the "what" is more important.
All depends on the change obviously but all commits that include a bugnummer should follow the convention. We can improve on the template in the wiki and e.g. require a Why and a What section. Requiring a specific message format forces us in the habit to think about the commit message. Also, new contributors have clear directions that we value the commit message.
Bug XXXXXX - Functional change in service XYZ
# Why
Service XYZ was not functional because things did not happen.
# What
Service XYZ was adjusted to make things happen.
Change-Id: I0000000000000000000000000000000000000000
Signed-off-by: Your Name <your.email@xxxxxxxxxxxx>
