well… dirty blender shot. using 1 rgba vertex color you can blend upto 5 materials with independent blend modulate texture projections/mappings. that’s more procedural and gives a different variety. while painting the blend modulate texture in engine is nice to author, you’re stuck at that one mapping and blend and have to generate a new blend texture for every piece you blend. increases texture memory. vertex color has a “lower” amount of data for large scale blending of low poly assets. for nanite geometry the texture is mosdef cheaper. depends on the balance of polygon count, the in engine blend textures and the “procedural” blend mods. you gotta use and recycle data efficiently. it’s really about balancing how much detail you need and how much data it generates.
on the shader level they are kinda equal. vertex color blend is “free”. it goes straight thru without any additional uvs and more data. and you gotta account for all texture samples either way.
