ELI5 Credit vs Debit Cards - what’s the difference?

What is the difference between swiping my bank card as a credit vs. a debit? Why do you need to use credit to get rewards points?  What role does Visa and Mastercard play in the process? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: bringer_of_words, tehwildman_, herohas, niuniu1218, civil_politics, goldzatfig, londonpilot and loodog To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: [email protected]