Credit card rewards vs savings on loan?

you have a big purchase like car or a home. Let’s assume your dealer/ builder accepts credit card without any additional charges and Merchant Code is also inline with their business.

A perfect situation to max out on swiping cards to hit those milestone or get those accelerated points or meet that spend offers?

Will you prefer swiping the card and paying the entire amount or take a loan and saving the amount in form of investment?