My thoughts on this:
Edge spots have a purpose. They are supposed to help distinguish chips from one another. Some considerations that come into play:
- Chips need to be distinguishable in poor lighting conditions. Consider changes in color temperature for mood lighting/dimmed light bulbs that lack in blue and sometimes even green parts of the visible spectrum, which might make colors like dark blue, dark green, dark grey, and black look all the same.
- Chips need to be distinguishable for players with impaired vision, too, including those with a color vision deficiency.
- Chips need to be distinguishable from a distance. At least from across the table and even further away, when we are talking about a casino environment.
- Chips need to be distinguishable from each other in a stack.
- In a casino environment, chips need to be distinguishable on camera surveillance. This is basically a repeat of all of the above, particularly in the earlier days when video surveillance did not have Full HD digital cameras with motorized zoom lenses, but simple black and white CCTVs.
Then we have economical (and security) considerations, too:
- In custom sets made by CPC, more complex edge spots will usually cost more; you probably would not want the chips you need the most of to be the most expensive ones.
- Casinos will likely want the lowest manufacturing cost anyway, but they certainly would not want to pay, let's say, $1.15 for a one dollar chip and lose 15 cents every time a tourist nicks a chip.
- Chips in a casino need to be different from those in a other venues.
- Chips need to have some form of protection against forgery, including simple relabeling of lower denom chip (potentially from a different casino). This is needed even with the availability of RFID when chips are exchanged directly between players, as is the case for poker.
I believe the last point is what led to the introducion of more complex edge spots for high denom chips, leading to the idea of "edge spot progression". While I like the concept, I personally would not stick to it very strictly if I was to create my own personal chip design.
I like idea of a higher value chip looking more sophisticated and "more valuable", but I would not prioritize this over all the other considerations. In the end, which spot spots are viewed as more valuable is a personal taste anyway.