They have loads of theoretical advantages :

1) spreadsheets are a purely functional programming language. When you point this out to management users of it (after explaining what it is), they wouldn't want to live without it.

So in reality the most widely used programming language in the world, is a purely functional one.

2) they are NOT turing complete (assuming you stay away from VBScript)

Of course, they're worse than BASIC when it comes to naming things, which is what everyone here is complaining about. But these are major advantages, to be fair. The only thing that comes even vaguely close to how spreadsheets work are the IPython notebooks.