The use of the 5 Nations title option is several fold.
Used predominantly, in fact almost exclusively in the amateurs, it provides a less complicated option for promoters and fighters alike.

The reality is that there is a fair amount of activity between the 'home nations' including Eire, and to travel between these countries is more practical and cost effective than moving out into Europe and beyond.
So once you move from domestic titles, the next sensible option is European. (I know that Commonwealth exists but it is hardly used).

The 5 Nations bridges that gap and allows decent contests to take place beyond domestic level without having to trail through Europe constantly looking for fighters whose records and level can be clarified.

For the main part, and under ideal circumstances we are able to follow a trail as most fighters in this category are on a smaller circuit and are aware or each other.

For instance there is a fair amount of activity between English & Irish fighters. Pull outs and problems aside, you can normally put a National or British champion with and Irish or All Irish champion to make a good contest.
If you are unable to (for instance) secure the British champion, you can go to the English champion and offer the 5 nations, in the hope that you can then match the winner at some point with the British champion if they so wish.

So rather than being 'just another title', it, in many ways replaces the European title initially and promotes activity and levels of progression for amateur, domestic fighters, setting up a whole host of options before moving on.

It has also helped to establish an ideal pecking order for European and then World honours.

I'm sure that those looking for it will find examples of less than ideal contests. It happens, for many reasons. we operate in an unpredictable industry. All you can do is look to have a plan to put that right moving forwards and maintain activity for keen amateurs.

I hope that helps with your question Lee.