It goes back to the customer..... The designer has to first remove his/her ego from the equation and ask the customer (usually the land owner) what they want from the course. What are their goals, needs, wants and desires? What will the land support. Now develop a design that accomodates each of those factors to the highest level possible.
Some courses only need/should have, a single set of tees and pin locations. They have specific purposes and won't be used for other things. The customer may request that there be only a single set of tees and pins.
Other courses can, and should have multi tee and pin locations. These tools can help control errosion, aid in player flow through the course, player satisfaction, and perhaps most importantly when dealing with short budgets, serve the broadest user group possible.
Grouping Red and Blue, White and Gold together keeps that player spectrum pretty high. Having multi pin locations to work with using two (or more) sets of tees makes it easy to custom fit your course for what's happening at that moment. E.g. you can have a short A pin location for your Scout/school/church demos, a B pin for day-to-day play, and a wicked C pin for tourneys (or an alt day-to-day).
Personally, I prefer well built and mantained grass tees. Easiest on the feet, ankles, legs, hips and back. Nice look too. Concrete is probably the default for most courses and locations. But I think that world class disc golf courses will start using other surfaces, like the rubber/poly-fiber/concrete sandwiches that are now covering many playground surfaces. These drain well, provide good grip and are still are easy on the body.
opcorn: