RE: Splinterlands: Kindred brothers came together!🔥

Buying cards to permanently add them to your deck is the best option, but renting seems like the right choice on the way to achieving that best option.
Because not every card that looks good will necessarily suit your battling style and strategies, therefore testing in multiple battles becomes crucial. Also, buying the cards can be quite expensive, so if you haven't come into the game with sufficient funds, renting them seems like the right way to go in that situation as well.