Some people have a priority because they want the colours to lineup with their other collectibles- an aesthetic preference whilst they are wrapped. Others have decided to take the risk on one colour of their choice, that it will have be a valuable collectible.
Everyone has a different reason but plenty of others just want one of each colour (in fact I think that’s what most want but idk for sure) so they want the next colour that they don’t have yet so that they have at least one of each new collectible. There are no differing values on each colour present. It’s entirely ambiguous as to what they will become.