No, there are no benefits attached to such cards. Giving out cards to donors is a common fundraising tactic for political candidates. “Membership” simply means that you have made a donation and contributed to the campaign.
Together with campaign merchandise, it’s often used to attract supporters to donate to their campaign and become a “card-carrying member”. Sometimes, these cards are even touted as limited edition to entice supporters to donate.
Buy an item from a campaign store, and you are not actually purchasing a product; you are making a donation. According to Federal Election Commission regulations, candidates are not allowed to sell items for personal profit, so the product is the “premium” you get in return for your pledge.
To highlight how ubiquitous this tactic is, here are some examples of cards given by political campaigns / organisations:
National Republican Congressional Committee
Democratic National Committee
Become a card-carrying member of the Democratic Party by making a $7 donation to renew your membership today.
Hillary Clinton’s presidential campaign
In 2016, Clinton’s campaign seized on a comment Trump had made and came up with the “women’s card” which led to a surge in donations ($2.4m to be exact).