When considering the combative nature of kata and how it fits into the civilian self-defence model of old-style karate (whatever 'old-style' may be, we'll leave for another blog post!), we have to first start with some simplistic truths. Once these are understood and appreciated, it is not too difficult to see how the movements of kata fit well into that model.
The first aspect to consider is that from a practical standpoint, there are really only two states when applying 'self-protection' against a threat to our safety. We are either 'escaping' from the threat, or we are 'engaging' that threat in such a way so that we may facilitate escape at the earliest appropriate opportunity. This is in stark contrast to consensual violence, where physical confrontation is actively sought out and time spent in that confrontation is often purposefully drawn out.
In terms of engagement ranges, there are again, really only two to be concerned with. You're either engaging the threat 'unattached' or engaging them 'attached'. These can of course be both pre-emptive and reactive, but the key contrast is the physical attachment. Your enemy may attach to you, you may attach to your enemy or both. Although crossovers exist, these two states require different combative tactics and it is obvious that being unattached will naturally facilitate an escape much easier than if already attached.
So based on the above, the list of priorities for the context of civilian self-protection may look something like this: