Thanks for the interesting post. Yes, the thoughts that you have raised is very similar to how depression is looked at from an evolutionary perspective, where it is said that depression is one of our basic responses to a variety of unpleasant events. And how, healthy levels of feeling depressed in response to a loss- either an actual one ( a death of a loved one) or a symbolic loss ( failure to achieve something important in life), helps us to understand and appreciate life in all levels.
If there wasn't something called depression, then we would start to feel unrelated to most of our emotions and feelings like love, anger, sadness, bereavement, gratitude, kindness, loneliness, friendship, detachment, sorrow, regrets, ambition, personal growth etc. Getting to experience and gain perspectives from these are unique to us humans. And even more so, is how we learn from our past and our mistakes and understand the different dynamics of how things work and how it affects us.
So, it is suffice to say that depression is not the villain we all thought it to be. And like everything else in this world, it works well in moderation. Since you do not consider it as a problem, then I guess that means you are able to function normally when it comes to your self concept/acceptance, your work and relationships despite having depressive symptoms. In right words, there is no significant impairment caused to you due to the symptoms.
However, depression can be a problem for many people since it starts to spillover the safety limits and starts to consume their thoughts and behaviour. Therefore, it is necessary for such people to accept that they have a condition and it needs to be addressed.