If you are paying OOP for Rainforest, IMHO, it makes sense to get the card. It's $25 and go towards your bill, so, even if you just use it only in WDW, I think it's worth it. I have a Landry's Card and only use it for WDW restaurants. I used up my welcome $25 years ago and rarely use the b-day bonus (as I don't seem to travel at that time anymore), but it's worth it's weight in gold when we walk right up to Rainforest or Y&Y and get in.
You can call the DS Rainforest. I'm not sure if you can call the AK Rainforest.