"Very Important" was my vote as well.
Personally, I think the term "Self Defence" can be a loaded statement, since it can imply many things that are not common to all or experienced by many. Imho self defence has a lot to so with the environment you commonly find yourself in, which is different for many of us.
In my environment it is important to be capable in being personally responsible for your own safety from personal attack at some level, since in most cases there is no one to come save you in case the inevitable hits the fan. To me, Self Defence is merely part of safety education (to quote a JAA Shihan as well). Same way one learns to swim if one lives on a small island
imo, or learns the correct way to cross the street.
To me, Aikido is Budo, which has many connotations, including "Martial Way" - which to me denotes a certain degree of combat effectiveness, or at least practice of combat principles while experiencing the "Way" in an effort towards self cultivation.
I understand those who do not practice Aikido for any reason related to self defence and this is fine by me. However, if there are no principles of combat being practiced, I would not call this sort of thing Budo either.
There is the philosophical aspect of having a pure heart and mind and not projecting a mindset of having to protect the self, since there is in fact no enemy and "the universe itself is our protector". Having at one time practiced that sort of thinking, I can say that it has its benefits, but to quote the signature of a fellow Aikiweb member: "Trust in Allah, but tie up your camel first."
Even though you seek peace and harmony, there are times you are in the presence of those whose sense of peace and harmony is best served by your own destruction, at least in their mind.
I think Aikido is all about taking the path of peace but being fully capable of dealing with those who want War, and still having the skill to not injure them, since you are in fact walking a path of peace and not destruction of your fellow man.
Of course I can also be totally wrong and full of BS as well.