wco81 - the Tourist card has:

- One or two AE ride
- 3 calendar days of MTR travel
- $20 to spend on other stuff, like ferries, buses, 7-eleven.
- $50 of deposit

The $50 1-day card has
- 24 hour or MTR travel

And again, you can use a credit card to get AE tickets, tourist passes and 1-day MTR pass. You cannot use one to get a regular Octopus card. I don't know if you can use a CC at a machine or not, but each station has manned ticket counter.