Hi @gmw ,
there is not really a difference, apart from Blender generalising Vertex Colors as Attributes.
This is the case since Blender 3.0.
This is 3.3:

and this was 2.93 LTS:

It is best if you stick to Blender 3.3 LTS and use Face Corner/Byte Color for your Assets.
You can use some earlier Versions, but I do not recommend using 3.4 or beyond (that is not backwards compatible).