I've given many more massages than I've received, (and picked up a suite of specific tricks or techniques for specific situations that I've never had employed on me), so this is by observation: massage is a direct benefit in many ways, and its actual benefits are often underestimated or overlooked in favor of placebo-based claims for other benefits.
As far as injury or disease recovery greater than with a whirlpool or the like I wouldn't know and rather doubt,
but something that makes you feel great and walk taller and concentrate more easily and even focus your eyes better,
and something that will, predictably in a defined time, remove specific pains and discomforts from specific places more or less permanently, and make a measurable and easily observed improvement in something like range of motion of your neck and head,
is not a placebo. It's a benefit.
I can, for example, relieve you quickly of some kinds of headaches that aspirin handles poorly, with none of aspirin's risks. I can get rid of a "knot", a sort of cramp, under your shoulder blade or inside your collar bone or at the base of your neck, that is ruining your day and possibly your week, in about three minutes. I can improve your posture, make you taller and better balanced, in about 20 minutes.
My guess is that there are some long term benefits in the way of lymph circulation and venous blood flow, and possibly blood flow to ligaments or other poorly irrigated places, but one would expect similar benefits from jacuzzis or yoga etc. One area massage may be uniquely beneficial is in hard bone manipulation - working the skull sutures, the thighbone sheaths. I don't really know, but people do feel better. Sometimes, a lot better for a long time.
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