It's likely that in this simple example the practical differences may be nonexistent. But if you think about the types represented and what they mean, RGB is no

It's likely that in this simple example the practical differences may be nonexistent. But if you think about the types represented and what they mean, RGB is not a color, but an encoding of a color. So if some function is supposed to take a color and RGB is used as a proxy for a color, you may very well be able to skip the abstraction but it would need to be refactored if you ever evolve into using the concept of a color and its presentation form in different ways. The class method seems to also allow CMYK and RGB to be defined completely independently of one another for any given color type. Whether that's necessary for the use case is beyond my understanding, but it allows that. I'd also imagine that giving colors their own types means that in the domain there's a small set of colors that are important, so a type class around this emphasizes the behaviors of these important colors rather than modeling a color system in general. Let's say one day RGB is superseded... while you can convert RGB values to any new value, you end up with all these functions that want to take a color, but are taking an RGB value instead. I do think that depending on the problem domain your method of treating colors as directly encoded values is valid, but maybe for a more robust color specific model than a color scheme application. I think a good analogy would be how to model a generic currency system, rather than the pricing plans of a SaaS app. The SaaS app will have some data StartupTier = StartupTier data ProTier = ProTier data EnterpriseTier = EnterpriseTier class IsPrice price where... instance IsPriceTier StartupTier where toUSD = const $ USD 5 Here it's not so much the currency system that we focus on than some discrete prices that we care about, that just so happen to convert to currencies. It also gives us the benefit of having tighter control on the different prices in different currencies rather than using a conversion function. Also that toRGB function has signature a -> RGB so it allows for a variable to perhaps dynamically calculate what RGB value it becomes... such as creating an instance of IsColor for something like "FavoriteColor" which could be pulled from the database.