福利遭到撤銷
Ben is explaining to Jane the downsides of co-branded credit cards.
本在向珍說明聯名信用卡的缺點。
explain sth. to sb. 向某人說明某事=explain to sb. sth.
Jane: I should sign up for a bunch of co-branded cards myself!
珍：我該申辦多張聯名信用卡！
sign up for sth. 報名～
Ben: Well, they’re not all rainbows and butterflies.
本：聯名信用卡可沒妳想的那麼美好。
all rainbows, butterflies and unicorns 極其美好的狀態
Jane: You mentioned that these cards are not good for carrying a balance. What other disadvantages do they have?
珍：你提過這些卡不適合積欠卡費，那它們還會有什麼缺點啊？
run up a debt 積欠債務interest rate 利率
Ben: Because of the intense competition, companies are offering increasingly better rewards to attract customers.
本：由於競爭激烈，各家公司不斷推出更好的獎勵制度吸引顧客。
compete(v.)競爭competitor(n.)競爭者competitive(adj.)有競爭（力）的fierce(adj.)激烈的attract(v.)吸引tourist attraction 旅遊景點
Jane: Isn’t that a good thing?
珍：這不是好事嗎？
Ben: It’s good for the time being, but it’s not a sustainable practice.
本：現在看來是好事，但這可不是長久之計。
for the time being=at this time=for now=for the momentsustainable(adj.)可持續的practice(n.)做法
Jane: Why not?
珍：為什麼？
Ben: These amazing rewards programs often create very thin profit margins for the companies offering them, so at some point, they may revoke card perks.
本：公司往往會因為推出這些獎勵方案而獲利單薄，所以就這點來說，他們可能撤銷聯名信用卡的福利。
profit margin 利潤幅度gross (net) profit margin 毛（淨）利revoke(v.)撤除、撤銷revoke a driver’s license 吊銷執照revoke a will 撤銷遺囑
Jane: Can they do that?
珍：他們可以那麼做喔？
Ben: They can. So you should continually review whether the card is still beneficial to you or not.
本：是可以的，所以妳該再三確認聯名信用卡是否還能讓妳持續受益。
be beneficial to 對～有利、有益的