That's not the same at all. Credit card transactions are auditable; just compare with the receipt. The same is not true of electronic voting machines with no paper trail.
What if the voting machines printed out a paper copy listing who you voted for that you could compare with a copy online listing who you voted for? It doesn't solve the problem of hacking electronic voting; that can only be solved by using paper votes. Sadly, until there's a mass voter fraud scandal, the majority of the public won't know or care about how vulnerable electronic voting is.
The machines San Mateo County uses do that. After you've made all of your selections, your votes are printed on a paper roll which appear behind a window, with a big bar code at the bottom. If you approve, the paper is wound out of view so the next voter can't see it. You can reject the printed version and go back, in which case the paper is marked with CANCELLED or something similar.
At the bottom of each voter's paper roll entry is a big bar code. This allows quick recounts by running the paper roll through a machine that reads the bar codes. A full manual check is also possible, but slow. The system goes through miles of thermal paper for each election, but works OK.
Voters should not be able to prove whom they voted for; enabling them to do so opens up the door to several kinds of fraud (vote buying, coercion, etc.).
There are some pretty neat solutions to this. One of them involves a double layer ballot+receipt. When viewed on top of each other, they spell out the vote, but alone the receipt will just give you enough information to see if your vote is counted or not:
Another scheme is giving away fake receipts in addition to or instead of "I voted" stickers.
OK VLM your boss needs a Trump receipt, your communist college professor needs a Clinton receipt, you need another Clinton receipt for facebook and github or they will delete your accounts, that'll be one R, three D, would you like any complimentary green party receipts? OK here's all your receipts thanks for voting see ya in 4 years!
Heck hand them out with the bake sale goods. Have a free set of pre-printed fake receipts for ALL the candidates with some delicious chocolate chip cookies that fund this schools PTA. "Could I interest you in this cageless chicken egg gluten free organic soy oil brownie with a complimentary fake green party receipt?"