[awhitty]

Hm, this is an interesting case where stylesheet design principles and application logic aren't so loosely coupled.

The data attributes almost seem to be a way to invoke CSS styles as functions themselves.

[goldenkey]

The main difference is that using classes, is misusing them. Because enum values as classes pollutes the namespace.

Enum values should map to attribute values. It makes logical sense. Attribute values don't go into a namespace. They just exist as things to query by.

It is possible many CSS engines optimize this fact. By not caching attribute values until there is a selector that uses them. Classes on the other hand are inherently saying 'I will query by this at a later time - I give no hints as to whether it is mutually exclusive with other class values. I merely have a list of class values which apply.'