I use it all the time! There, I said it.
I use it because it's HEAPS cheaper than the fancy stuff at bike shops, it seems to attract much less crud than oil, and, best of all, I can buy it from any supermarket at 2am!
When it comes down to it, the chain and cassette are only temporary, relatively inexpensive items, so it ain't crucial if they aren't perfectly maintained.
I still manage to get many thousands of kms out of my chains and cassettes