one problem with a blood texture would be that you can just colour it in, say void and have void blood, which costs $20. this means they have to make the texture more expensive than most of the blood colours, making it too expensive to be worth it. the same effect can be achieved with body textures, but because an actual texture looks much better than just block colours, it doesn't matter. this is why they made joint textures cost money, rather than tc (i think)