New Scientist article:

Time spent in communal non-productive endeavours creates a bonding. Ideal for tribal unity. We are, after all, a herding pair-bonding species. And tribal unity can not be more evident than at a soccer game. "Us & Them", communal singing, and partisan crowds.

We can expend 16% more energy exercising to music. Think Shanties. And be more synchronised.

And I have seen (on telly) people suffering Parkinson's who are able to walk (cf not being able to) albeit obviously impaired, whilst listening to certain types of music. MP3's being a "prosthetic" then.

I like the mnemonic aspect highlighted by mg

And story-telling is easier with rhyme. Moral tales like "Bunch of Thyme" could be taught to very young juveniles.