I think you're all overthinking it. I'm not any sort of medic, and I don't even play one on TV, but here's my take. The absorbent properties are there just so you don't make a mess of things around you, dripping blood everywhere.

That reminds me of one of my knee surguries. The doctor repaired some cartiledge, and he deliberately caused some bleeding to attempt to nourish the cartiledge to help it heal. A lot of that blood ended up in the dressings. The doctor didn't tell me about that at the time, so I was suprised at how much blood there was when I took it off. So I set it aside to ask my wife about it, since she's a physician. Well, my dog ate it in the meantime!