well, you use ether to buy alpacas once you have an alpaca you can breed it to get more alpacas. you can also feed it ether and it would generate wool which I also etherium.
you can learn how to play with more detail here: https://medium.com/@CryptoAlpaca/cryptoalpaca-beginners-guide-b40c58336f4
Thank you for information, but I always wonder some questions about those kind of websites. How do they mine cryptocurrencies and how does website admin earn money? Do you know about it?
as far as i'm aware they do not mine crypto. And they earn money as you use the game. they are fees for selling and breeding the alpacas
I think it doesn't fit to my mind lol. But it's possible, because we have a farm which pays to users of website.